914World.com > Electrical problems

watsonrx13

Aug 13 2008, 07:01 PM

I've been trying to track down an electrical problem with my FI and I've found more problems.

1. When I turn on the ignition switch I blow fuse #9. The Haynes manual says that this fuse powers the turn signals, brake lights and back-up lights. Also, I noticed that the buzzer sounds when I turn on the key, regardless of both doors closed or open. Anyway, I disconnected the brake light switch at the brake pedal, all of the wires to the turn signals and disconnected the back-up light wire at the tranny but the fuse still blows, which then stops the buzzer.

2. No power to the coil. I've replaced the ignition switch with another one, but I'm still not getting any power at the coil. I've checked the continuity between the ignition switch and the coil.

I have power to all pin #30s on the relay board in the engine compartment. I have power at the large red wire at the ignition switch.

I feel that I'm very close to getting this car running, but with these electrical gremlins I'm extremely frustrated...

Any suggestions and/or guidance would be greatly appreciated....

-- Rob

904svo

Aug 13 2008, 08:05 PM

Try this remove fuse #9, using a volt meter or trouble light check
1. Turn on key, one side of the fuse should have 12 volts on it (Black wires on it)
these wires go to the ingition swich and to the relay board which supply power to the coil and other relays. If this is OK check the following

2. Problem must be on the black/yellow wire ( brake switch) or
the red/white wires which power the gauges and the emergency flasher switch
if you disconnect these wires and reattatched them one at a time you can find
out which wire is causing you a problem which you can track down the problem.

hope this helps you

r_towle

Aug 13 2008, 08:46 PM

What year car is it?
Does it have the logic circuit under the passenger seat???
Rich

swl

Aug 13 2008, 09:13 PM

It almost sounds like you might have multiple problems. 904svo's advice sounds pretty good to me. The routing of the power for the coilis really straight forward. from the switch to fuse s9 then back to the relay board. The power does not go through the fuse. It is only a connection point. On the relay board that power should be present on pin 8 of the 14 pin connector, pin 7 of the 12 pin connector and on pin 85 of both the main power and heater blower relays. Take out fuse 9 and work on the coil cct first - it will help keep things a little more simple.

Again to simplify things - take the power lead off the coil while you are doing your trouble shooting

orange914

Aug 13 2008, 11:33 PM

QUOTE(watsonrx13 @ Aug 13 2008, 06:01 PM)

1. When I turn on the ignition switch I blow fuse #9. The Haynes manual says that this fuse powers the turn signals, brake lights and back-up lights.
-- Rob

sounds like you have a direct short. since the turn/brake lights are in the curcuit, have you messed with the bulbs previous to the problem? a 1156 inserted 180* off will do odd things. how about the 1156 in the 1157 spot or visa-versa? been there, done that, got the t-shirt

mike

watsonrx13

Aug 14 2008, 06:52 AM

Thanks everyone for your replies...

QUOTE(904svo @ Aug 13 2008, 09:05 PM)

Try this remove fuse #9, using a volt meter or trouble light check
1. Turn on key, one side of the fuse should have 12 volts on it (Black wires on it)
these wires go to the ingition swich and to the relay board which supply power to the coil and other relays. If this is OK check the following

2. Problem must be on the black/yellow wire ( brake switch) or
the red/white wires which power the gauges and the emergency flasher switch
if you disconnect these wires and reattatched them one at a time you can find
out which wire is causing you a problem which you can track down the problem.

hope this helps you

1. I'll check this circuit and report back later today...

2. I should disconnect the black/yellow wire at the brake switch on the brake pedal? I should disconnect the red/white wires at the head light switch in the dash? I should disconnect the red/white wire at the emergency flasher switch in the dash?

QUOTE(r_towle @ Aug 13 2008, 09:46 PM)

What year car is it?
Does it have the logic circuit under the passenger seat???
Rich

Sorry, it's a '74 2.0l and I've already bypassed the passenger seat circuit...

QUOTE(swl @ Aug 13 2008, 10:13 PM)

It almost sounds like you might have multiple problems. 904svo's advice sounds pretty good to me. The routing of the power for the coilis really straight forward. from the switch to fuse s9 then back to the relay board. The power does not go through the fuse. It is only a connection point. On the relay board that power should be present on pin 8 of the 14 pin connector, pin 7 of the 12 pin connector and on pin 85 of both the main power and heater blower relays. Take out fuse 9 and work on the coil cct first - it will help keep things a little more simple.

Again to simplify things - take the power lead off the coil while you are doing your trouble shooting

So, I should take the fuse out of #9, turn on the ignition switch and check power at pin 8 of 14, pin 7 of 12 and pin 85 of relay 74. When I check the pins of the connectors, should I have the connectors installed in the relay board with the cover off or just pull the connectors and check the pins? Should I pull the relay and check the socket or wrap a wire around the pin, reinstall the relay and check power then?

QUOTE(orange914 @ Aug 14 2008, 12:33 AM)

sounds like you have a direct short. since the turn/brake lights are in the curcuit, have you messed with the bulbs previous to the problem? a 1156 inserted 180* off will do odd things. how about the 1156 in the 1157 spot or visa-versa? been there, done that, got the t-shirt

mike

I haven't messed with any of the bulbs, but I did clean up all of the sockets prior to reinstallation....

Something else that I just remembered, all of the light circuits were working well and no issues with the fuses prior to me dropping the engine/tranny. This problem only came up once I reinstalled, so, is it possible that I might have pinched a wire somewhere when I reinstalled the engine? If so, do I need to drop the engine and recheck all of the wire?

-- Rob

swl

Aug 14 2008, 08:12 AM

QUOTE(watsonrx13 @ Aug 14 2008, 04:52 AM)

So, I should take the fuse out of #9, turn on the ignition switch and check power at pin 8 of 14, pin 7 of 12 and pin 85 of relay 74. When I check the pins of the connectors, should I have the connectors installed in the relay board with the cover off or just pull the connectors and check the pins? Should I pull the relay and check the socket or wrap a wire around the pin, reinstall the relay and check power then?

I would start with one of the relays since that is easiest. Just take it out and measure at the socket. If no joy there, disconnect the 14 pin and look for power on pin 8 of the wiring harness. If still no joy go back and measure the black wires attached to fuse 9.

orange914

Aug 14 2008, 10:51 AM

QUOTE(watsonrx13 @ Aug 14 2008, 05:52 AM)

QUOTE(orange914 @ Aug 14 2008, 12:33 AM)

sounds like you have a direct short. since the turn/brake lights are in the curcuit, have you messed with the bulbs previous to the problem? a 1156 inserted 180* off will do odd things. how about the 1156 in the 1157 spot or visa-versa? been there, done that, got the t-shirt

mike

I haven't messed with any of the bulbs, but I did clean up all of the sockets prior to reinstallation....

Something else that I just remembered, all of the light circuits were working well and no issues with the fuses prior to me dropping the engine/tranny. This problem only came up once I reinstalled, so, is it possible that I might have pinched a wire somewhere when I reinstalled the engine? If so, do I need to drop the engine and recheck all of the wire?

-- Rob

so if i understand you, you did remove the bulbs to clean the sockets AT the time of the install. if so did you test and confirm good operation of the lights before the problem showed up?

i think you've got good advice to trace it back to find where the problem lies, beginning from the start of the power feed to the end of the loop. start from one end or the other, but not somewhere inbetween. i just try to rule out any easy to check, possible oversights (mistakes of recent repairs or pinch possibilities) before digging in. a shorted to ground (pinched wire) is a good posibility if the wires are in the area. an improperly installed or wrong bulb can and/or will direct power to ground, blowing the fuse. by the way, at least the 914's i've seen, seem to corrode in the sockets. when we cleaned ours we used di-electric grease hoping to help preserve the connections, seems to have worked. good luck

watsonrx13

Aug 14 2008, 12:18 PM

QUOTE(orange914 @ Aug 14 2008, 11:51 AM)

QUOTE(watsonrx13 @ Aug 14 2008, 05:52 AM)

QUOTE(orange914 @ Aug 14 2008, 12:33 AM)

sounds like you have a direct short. since the turn/brake lights are in the curcuit, have you messed with the bulbs previous to the problem? a 1156 inserted 180* off will do odd things. how about the 1156 in the 1157 spot or visa-versa? been there, done that, got the t-shirt

mike

I haven't messed with any of the bulbs, but I did clean up all of the sockets prior to reinstallation....

Something else that I just remembered, all of the light circuits were working well and no issues with the fuses prior to me dropping the engine/tranny. This problem only came up once I reinstalled, so, is it possible that I might have pinched a wire somewhere when I reinstalled the engine? If so, do I need to drop the engine and recheck all of the wire?

-- Rob

so if i understand you, you did remove the bulbs to clean the sockets AT the time of the install. if so did you test and confirm good operation of the lights before the problem showed up?

i think you've got good advice to trace it back to find where the problem lies, beginning from the start of the power feed to the end of the loop. start from one end or the other, but not somewhere inbetween. i just try to rule out any easy to check, possible oversights (mistakes of recent repairs or pinch possibilities) before digging in. a shorted to ground (pinched wire) is a good posibility if the wires are in the area. an improperly installed or wrong bulb can and/or will direct power to ground, blowing the fuse. by the way, at least the 914's i've seen, seem to corrode in the sockets. when we cleaned ours we used di-electric grease hoping to help preserve the connections, seems to have worked. good luck

Thanks for the suggestions.... I wasn't clear about the cleaning.... After I cleaned I tested all of the lights and they were working correctly.... I'll definately follow your advice about starting at one end or the other....

-- Rob

watsonrx13

Aug 14 2008, 04:33 PM

Steve, I followed your instructions and found the problem....

There was no power at pin 8 of 14, because the black wire/socket was in pin 6. I swapped the wire and the fuel pump is now working. Thanks again for taking the time and having patience to walk me through these steps. I feel much more comfortable looking at the relay board wiring and the main wiring diagram. I haven't tried to start it today, I'm waiting for another set of eyes and hands so that if there's a fuel leak, we can stop it immediately...

-- Rob

QUOTE(swl @ Aug 14 2008, 09:12 AM)

QUOTE(watsonrx13 @ Aug 14 2008, 04:52 AM)

So, I should take the fuse out of #9, turn on the ignition switch and check power at pin 8 of 14, pin 7 of 12 and pin 85 of relay 74. When I check the pins of the connectors, should I have the connectors installed in the relay board with the cover off or just pull the connectors and check the pins? Should I pull the relay and check the socket or wrap a wire around the pin, reinstall the relay and check power then?

I would start with one of the relays since that is easiest. Just take it out and measure at the socket. If no joy there, disconnect the 14 pin and look for power on pin 8 of the wiring harness. If still no joy go back and measure the black wires attached to fuse 9.

watsonrx13

Aug 14 2008, 04:43 PM

QUOTE(904svo @ Aug 13 2008, 09:05 PM)

Try this remove fuse #9, using a volt meter or trouble light check
1. Turn on key, one side of the fuse should have 12 volts on it (Black wires on it)
these wires go to the ingition swich and to the relay board which supply power to the coil and other relays. If this is OK check the following

2. Problem must be on the black/yellow wire ( brake switch) or
the red/white wires which power the gauges and the emergency flasher switch
if you disconnect these wires and reattatched them one at a time you can find
out which wire is causing you a problem which you can track down the problem.

hope this helps you

I've have some updated information....

1. I have 12 v on the black wires ....

2. I found where the wires connect to the brake switch and disconnected them. I disconnected the red/white wires from behind the instrument cluster, but only the one that came off of the main wiring harness. I know that the other red/white wires are in series, so I was hoping that I only had to disconnect the first one in the loop. I ran out of time, before the storm set in, but I'm assuming that I just need to reach behind the dash and disconnect the red/white wire to the emergency flasher? Anyway, with only the emergency flasher connected, I installed the #9 fuse and turned on the ignition, it still blew the switch...

I do have a question about the brake switch. There are (2) sets of wires hooked to the switch. One group only has a black/yellow wire. The other group has a white/brown, red/white and a black/yellow wire. Is this correct? It doesn't seem that there should be a black/yellow wire on both sides of the switch....

Thanks again for the assistance....

-- Rob

904svo

Aug 14 2008, 10:05 PM

QUOTE(watsonrx13 @ Aug 14 2008, 02:43 PM)

QUOTE(904svo @ Aug 13 2008, 09:05 PM)

Try this remove fuse #9, using a volt meter or trouble light check
1. Turn on key, one side of the fuse should have 12 volts on it (Black wires on it)
these wires go to the ingition swich and to the relay board which supply power to the coil and other relays. If this is OK check the following

2. Problem must be on the black/yellow wire ( brake switch) or
the red/white wires which power the gauges and the emergency flasher switch
if you disconnect these wires and reattatched them one at a time you can find
out which wire is causing you a problem which you can track down the problem.

hope this helps you

I've have some updated information....

1. I have 12 v on the black wires ....

2. I found where the wires connect to the brake switch and disconnected them. I disconnected the red/white wires from behind the instrument cluster, but only the one that came off of the main wiring harness. I know that the other red/white wires are in series, so I was hoping that I only had to disconnect the first one in the loop. I ran out of time, before the storm set in, but I'm assuming that I just need to reach behind the dash and disconnect the red/white wire to the emergency flasher? Anyway, with only the emergency flasher connected, I installed the #9 fuse and turned on the ignition, it still blew the switch...

Disconnect the wires from fuse #9 the black/yellow supply power to the brake lights if this wire is disconnected and it still blows the fuse it's not the problem.
I would supect the red/white wire is connected wrong some where. one red/white
wire runs to terminal 15 on the emergency switch, the other red/white wire runs to the gas gauge (3 places) two light bulbs sockets then to #15 , then to the tach (#15). I would supect one of them is connected wrong

I do have a question about the brake switch. There are (2) sets of wires hooked to the switch. One group only has a black/yellow wire. The other group has a white/brown, red/white and a black/yellow wire. Is this correct? It doesn't seem that there should be a black/yellow wire on both sides of the switch....

The black/yellow run to the tail lights (stop lamp) the red/white runs to the connector for the gauges in the console the gray/brown runs to #3 terminal
on the relay plate and comes out on #2 to the back up light switch. Note these
wire are power feeds.

This is correct by my wiring diagram.

Thanks again for the assistance....

-- Rob

orange914

Aug 14 2008, 10:35 PM

so to summerize you found a incorrectly placed wire and switched it. you now have power to the fuel pump.

i have to assume the fuse still blows because you are tracing wires in your next post. did you double check that back up bulb socket has a single element bulb and the brake/driving light sockets have double element (and not installed 180* off)?

mike

Dave_Darling

Aug 14 2008, 11:26 PM

Double- and triple-check the plugs on the relay board. They're keyed so you shouldn't be able to plug them in "off by one" pin, but you can if you try... It causes all kinds of "stuff does not work" problems.

--DD

swl

Aug 15 2008, 08:48 AM

Well done Rob! You are half way there. Now get at the bulb cct.

Finding shorts is not always easy. So be methodical.

Dave - If I'm following Rob correctly someone installed the black wire into the plug at location 6 instead of location 8. Location 6 is normally blank so it is easy to do this.

watsonrx13

Aug 15 2008, 09:00 AM

QUOTE(Dave_Darling @ Aug 15 2008, 12:26 AM)

Double- and triple-check the plugs on the relay board. They're keyed so you shouldn't be able to plug them in "off by one" pin, but you can if you try... It causes all kinds of "stuff does not work" problems.

--DD

Thanks Dave I will....

Here's what I got from the wiring diagram, is this correct for the T14 connector?

1. yellow
2. blue
3. white/brown
4. white/brown
5. green/red
6. ------------- NOT USED -------------
7. black/purple
8. black
9. green/white
10. brown
11. green
12. red
13. black/red
14. red

-- Rob

watsonrx13

Aug 15 2008, 09:01 AM

QUOTE(orange914 @ Aug 14 2008, 11:35 PM)

so to summerize you found a incorrectly placed wire and switched it. you now have power to the fuel pump.

i have to assume the fuse still blows because you are tracing wires in your next post. did you double check that back up bulb socket has a single element bulb and the brake/driving light sockets have double element (and not installed 180* off)?

mike

Mike, I'll recheck these bulbs this weekend....

-- Rob

watsonrx13

Aug 15 2008, 09:05 AM

QUOTE(904svo @ Aug 14 2008, 11:05 PM)

Disconnect the wires from fuse #9 the black/yellow supply power to the brake lights if this wire is disconnected and it still blows the fuse it's not the problem.
I would supect the red/white wire is connected wrong some where. one red/white
wire runs to terminal 15 on the emergency switch, the other red/white wire runs to the gas gauge (3 places) two light bulbs sockets then to #15 , then to the tach (#15). I would supect one of them is connected wrong

I do have a question about the brake switch. There are (2) sets of wires hooked to the switch. One group only has a black/yellow wire. The other group has a white/brown, red/white and a black/yellow wire. Is this correct? It doesn't seem that there should be a black/yellow wire on both sides of the switch....

The black/yellow run to the tail lights (stop lamp) the red/white runs to the connector for the gauges in the console the gray/brown runs to #3 terminal
on the relay plate and comes out on #2 to the back up light switch. Note these
wire are power feeds.

This is correct by my wiring diagram.

Thanks again for the assistance....

-- Rob

When I originally tested all of these lights/gauges, I now remember that I had the fuel tank completely emptied. Also, I removed the instrument cluster, so I'm suspecting that I have the fuel gauge wired wrong....

-- Rob

swl

Aug 15 2008, 09:17 AM

QUOTE(watsonrx13 @ Aug 14 2008, 02:43 PM)

I do have a question about the brake switch. There are (2) sets of wires hooked to the switch. One group only has a black/yellow wire. The other group has a white/brown, red/white and a black/yellow wire. Is this correct? It doesn't seem that there should be a black/yellow wire on both sides of the switch....

Have a look at the current flow diagram for 1974 usa part 2. The cct we are looking at is on the left hand side of the diagram with the fuse 'S9' near the top of the page and the brake switch 'F' near the center. Power is coming from S9 by way of the bk/yw into a connection cluster of 3 wires. from that connection point power flows to the backup light switch 'F4' by way of the GY/BR (gray brown) wire. This switch is back on your transmission. It looks to me like the red white takes power to 'G9' oil temp indicator and 'G14' volt meter.

the black/yellow on the other side of the brake switch takes the power to the lights themselves when the switch is closed. So yes what you are seeing is consistent with the wiring diagram.

Suggestions:
with power off - Lift the gy/br and rd/wh from that connection point and measure with your ohm meter between ground and each of those wire ends. Also measure from ground to the remaining connector on the switch. You are looking for the branch that measure really low - 1 ohm'ish or lower

watsonrx13

Aug 19 2008, 02:06 PM

Latest update:

Well, I'm out of town this week, but thought that I'd give you guys an update. Before I left, Saturday, I had the dash out, the ignition switch out and was testing ALL of the recommended wires and/or connections. I was finally able to turn the ignition on without the fuse blowing....

, but I don't know exactly what I did.

Anyway, I put the dash and steering wheel back together. As I put one major section back in, I tested the fuse. Everything working great. So, I was ready to start the engine. Turn on the ignition, POW, there goes the fuse. WTF????? Anyway, before I started taking everything apart again, I got underneath the dash and started looking for loose wires. Well I found (2). One was a red wire, for the radio which I had removed, and another was a red/white wire that was suppose to be attached to a dash illumination bulb, it was touching the dash. So, I replaced the fuse, held the wires away from the dash and turned on the ignition. No problems.

So, I think I found my problem, but I still want to check a couple of more things....

-- Rob

swl

Aug 19 2008, 05:47 PM

great job Rob.

watsonrx13

Aug 24 2008, 01:31 PM

QUOTE(swl @ Aug 19 2008, 06:47 PM)

great job Rob.

Well, I'm back in town and working on the car. The loose red/white wire was definately shorting out on the dash. I plugged it back and and no more fuse popping.... Steve, thanks again for taking the time and effort to help me with this problem... 904svo, it was your suggestion that was the final solution, thanks again....

-- Rob