Last week I swapped out the ignition tumbler then started having electrical problems. I decided this weekend I would try to tackle them. BTW, I have a '74 2.0l FI. Here's the situation:

When I turn the ignition switch on, I don't get any power to the fuse panel nor the fuel pump nor the starter. Before swapping the tumbler, everything was working fine, except the headlights wouldn't raise. They would light up, but not pop up.

So, I checked the wiring diagram. Here's my interpretation of the ignition switch.....

30 - power from the battery (red)
X - headlight switch (red)
15 - fuse #9 (black) & seat belt warning light (red)
P - starter
S - seat belt warning w/buzzer(gray/brow)
50 - seat belt warning w/buzzer (yellow)

I pulled the tumbler and checked for power at ignition plug #30 - good - 12v
When I turn the key, I get power to fuse #9 (12v). Also the seat belt warning light comes on (the one in the dash above the vent controls). When I close the doors, the light doesn't lite up. The seat belt buzzer sounds, but stops when the doors are closed.

Looking at the diagram, it appears that there should be power to the red wire at fuse #11. I checked and nothing. I decided to place a wire directly from the battery to the #11 fuse. When I installed this wire, my headlights raised and lit up. The fog lights worked. The windshield wipers worked. The turn signals worked.

Is there suppose to be a direct connection between the battery and the fuse panel? And if so, where is the conection?

I think the ignition switch is bad, but I swapped out (2) others that I have in my stash, but they didn't work either. Joe has suggested that I remove the ignition switch from the tumbler and use a small screwdriver to turn the switch, which I'll perform tomorrow.

Any suggestion? BTW, I don't have internet connection at the shop, so I won't be able to check until tomorrow.

-- Rob

Also, can someone confirm the location of the red wires from the battery?

1. Pin #12 on 14-pin connection in the engine compartment
2. Pin #14 on 14-pin connectionin the engine compartment
3. Ignition switch
4. Fuse #11 on the fuse panel in the passenger compartment.

-- Rob

I can tell you that part of the panel is hot all the time.

Great, can you tell me where the hot wire is connected on the panel?

-- Rob

Just got back from testing the ignition switch. I removed the switch from the tumbler, plugged it back into the wiring harness and used a small bladed screwdriver to turn the center section of the switch. Nothing, I still don't have power to the starter. BTW, the large yellow wires underneath the passenger seat are spliced together, bypassing the relay.

Anyother suggestions?

-- Rob

Fuse #11 gy/rd wire on one of the diagrams I have. Red from 2nd diagram ?
fuse #7 gy wire from battery
Hope that helps

Steve

I bought a new ignition switch and tested it. It works great, but I still can't turn the starter on or run the fuel pump or get power to the fuse panel. If I remove the large red wire from fuse #12 and replace with a wire directly from the battery, I get power to fuse #10, 11, 12 and the headlights, fog lights and wipers work.

I'm going to verify that the tranny ground strap is attached and try to jump the starter.

Any other recommendations? Is there any designed break in the wiring from the battery to the fuse panel?

-- Rob

Relay. and I can't remember where it's at. but I don't think you are picking it up to route power to the fuse panel.

I amended your list of items powered by contacts on the ignition switch. Changes include:
15 power the FI relay and heater relay
P is power for parking lights when key is off
50 is the starter signal.



30 - power from the battery (red)
X - headlight switch (red) + Fresh Air Blower
15 - fuse #9 (black) & seat belt warning light (red) + Seat belt warning system Relay & buzzer, engine ignition (coil), turns on relay for FI, power to heater relay coil
P - Parking lights when key is off
S - seat belt warning w/buzzer(gray/brow)
50 - seat belt warning w/buzzer (yellow), starter signal




The only fuse the ignition switch turns on is 9. If you have power there you have all the power to the fuse panel that the ignition switch controls.

To test your ignition switch, do this process:
1) disconnect ignition switch from car.
2) Place your voltmeter on ohms and connect one wire on 30. All measurements are made from 30 to another contact.
3) Test 15: put other wire from ohmmeter on 15. measure ohms (Inf.=infinity, ie. no connection):
OFF RUN START
Inf. 0 0
4) Test X: put other wire from ohmmeter on X. Measure ohms:
OFF RUN START
Inf. 0 Inf.
5) Test P: put other wire from ohmmeter on P. Measure ohms:
OFF RUN START
0 Inf. Inf.
6) Test 50: put other wire from ohmmeter on 50. Measure ohms:
OFF RUN START
Inf. Inf. 0

If you measure these resistances, your ignition switch is ok. This doesn't mean your wiring is ok, just your switch is ok.


If you don't have power on fuses 10-12, then this in totally independent from the ignition switch. There is a red wire on either fuses 10, 11, or 12, this wire is your problem. This wire goes directly to the battery. You must follow this wire to see that it's connections are ok.

Word of Caution. Wire to #30 on the ignition switch and the wire to fuses 10-12 come directly from the battery with no fusable links. This means the amount of current available on these wires are limited by the wire itself. If you accidentally short any of these wires to ground, you most likely will hear a pop or pow and see sparks as the wire destroys itself. Be very careful when moving these wires. Disconnect battery NEG when making changes to the wiring or doing experiments.

This immediately needs to go to the classic thread place to keep forever.
Best damn "how to" trouble shoot ignition switch explaination I've ever read.

I told Rob this procedure over the phone this past Friday. Guess I should have wrote it down.

Thanks Spoke for the correction and the testing. I definately have power to 30 in the wiring connection. I'll need to find the issue with the red wire going from the battery directly to the fuse panel, on mine, I think it's fuse #12. I've already purchased a new ignition switch, but I'm still not getting the power to the starter or the fuel pump. I'll have to trace the wires in each loop to figure out what's wrong... or I'm justing going to run a new red wire to the fuse from the battery...

Oh yea, thanks again Joe for the suggestions 'Hey take the switch out and use a screwdriver to turn it, see if that fixes it'.....

-- Rob

The seat belt relay assembly does something with the starter signal to the starter. Power from one of the F10-F12 fuse goes to this assembly. If power is not on the fuses, then the starter will not start.

About the FI fuel pump, do you hear the 2 second startup when you put the key in the RUN position?

My guess is that the "no power to fuses 10-12" is causing all your problems.

Question: What was happening with your car before you changed the ignition switch?
What wasn't working before you changed the ignition switch?

On the fuse block fuses 10,11,12 are strap toghter, Check your straps.

Question: What was happening with your car before you changed the ignition switch?
What wasn't working before you changed the ignition switch?
[/quote]

His fingers were under the dash.

[font=Arial][size=7][quote name='Joe Ricard' date='Nov 18 2008, 01:43 PM' post='1103131']
Question: What was happening with your car before you changed the ignition switch?
What wasn't working before you changed the ignition switch?
[/quote]

His fingers were under the dash.
[/quote]
I need the wireing pattern for a 914-6 ignition switch. When I put a new electrical part on the wires popped off! I am not sure I got tham back on correctly. Any sugestions?

I swapped out the igition tumbler... becauseI lost the key....

I had been having problems with the headlights raising....The wipers weren't working, so I think I was having problems before the tumbler swap....

Prior to the tumbler swap, I was diagnozing the FI... I was finally able to successfully run the fuel pump and get all of the FI components to work properly. I could hear the 2 second start up before, but not now. The idle was 1200-1500 cold, then 900-1000 warm. I'm going to do some more testing of the circuits tomorrow, so stay tuned and thanks again for the suggestions...

-- Rob

Here's a link to a thread that may help.

Ignition switch engagement troubles

Thanks. Daniel

New update..... I can start and run the engine.... In regards to the ignition switch, I checked it first with the screwdriver, then reinstalled and it works correctly...

I still don't have power to the fuse panel. I found a large red wire with a splice in it, but after removing the spice, it didn't have power, it was attached to the #12 fuse. So I'm still trying to track down the lack of fuse panel power.

While I have the dash and fuse panel apart, I'm going to verify that ALL electrical parts are working .....

Thanks again for everyone's suggestions....

-- Rob

The large red wire on lug #12 goes to the fresh air relay, the two red wires on lug#11 one goes to the battery the other to the horn relay. the one on lug #10
goes to light switch. Also lugs #10,11,12 are strap toghter.

Thanks.... now where is the fresh air relay and the horn relay?

-- Rob

Those are on the interior fuse panel. Check Haynes p. 128 or factory manual.

I had some intermittent starting issues that were fixed by bypassing the seat belt warning system. There's a how-to on this board somewhere.

Well, I finally found the problem with no power to the fuse panel. The DAPO cut ALL of the red wires from the battery, then spliced them back together. I don't understand why, but the splice was hidden by black electrical tape and the wiring loom was underneath the FI box. Here's a shot of the splices....

Click to view attachment

After I found and fixed this problem, all of my other electrical problems were fixed, except the driver's front blinkers. I checked power to the blinker and the running light's wires, but the light wouldn't lite up. I replaced the blinker housing and everything worked correctly.

Thanks again to everyone.

-- Rob

Are your other connections there are ok? Hopefully you've checked them all. I don't trust wire splices w/o solder and crimp connectors.

Secure wire connections and splices are foundations of reliable electrical systems. For splices I always twist the wires together and solder. Electrical tape or shrink wrap and that connection will never need maintenance.

Crimps make good connections on day one then go downhill after that. They can loosen up if the wires are moved or vibrated. Twisted spices w/o solder can un-twist and make intermittent contacts. Both types can cause strange behavior of the electrics.

Spoke, I did check all of the connections and they appeared very secure. Also, I've taped the red wire on the outside and didn't try to 'hide' it, it makes it more convient to check and test in the future.

As the other knowledgable and experienced members have mentioned, these electrical problems are managable and correctable, you just have to be willing to listen to the recommendations and spend the time tracing the wires. For any of the newbies, you need to know where the power is coming from and trace it throughout wiring diagram. Once you know the starting point, it's pretty straight foward.

-- Rob