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914World.com _ 914World Garage _ No Rear Brake Lights...Most Likely?

Posted by: kenshapiro2002 Aug 4 2009, 07:37 PM

Just figured this might be a common 914 thing that ya'll had experience with. I hate electrical work, and am not too good at diagnostic.
Ken

Posted by: geniusanthony Aug 4 2009, 08:40 PM

Ken, the easiest thing is to probably check in the trunk first at the bulb socket for voltage. If that fails I would check the switch under the footwell board attached to the pedal stop. There are two wires that connect here and there is an adjustment as well. Additionally the brake light circuit is keyed I believe, at least on my car it is. If you dont have the manual you can download one from the pelican site and print it out in color(helpful) or what I did and have it blown up and laminated at a Kinkos. Good luck.

Posted by: kenshapiro2002 Aug 4 2009, 08:48 PM

Meaning it's not "hot"...only works when ignition is on?
Ken


[quote name='geniusanthony' date='Aug 4 2009, 10:40 PM' post='1199424']
Additionally the brake light circuit is keyed I believe, at least on my car it is.

Posted by: geniusanthony Aug 4 2009, 09:07 PM

That has been my experience. Without looking at the diagram I cannot say whether or not that is how it is supposed to be or if it is a DAPO-Mod.

Posted by: jt914-6 Aug 4 2009, 09:14 PM

Yes, the key has to be "on" for the brake lights to work..As was said, check voltage at bulb socket, if no voltage check the brake light switch in the pedal assm. Check that both wires are attached and adjust the switch. We assume that you have checked fuses....

Posted by: championgt1 Aug 4 2009, 10:35 PM

I would check the fuse under the dash. It is easy to knock out getting in and out of the car, especially if you don't have the fuse panel cover. Been there done that!

Posted by: kenshapiro2002 Aug 4 2009, 10:45 PM

I have a cover and the fuses all seem to be fine.
Ken

QUOTE(championgt1 @ Aug 5 2009, 12:35 AM) *

I would check the fuse under the dash. It is easy to knock out getting in and out of the car, especially if you don't have the fuse panel cover. Been there done that!


Posted by: kwales Aug 5 2009, 09:08 AM

Tried the brake light switch?

It's down in the pedal cluster/ cover plate area and it actuates off the brake pedal. Use a VOM with a continuity setting to check. If the switch doesn't trip when the brake pedal goes in and out, there's yer problem.

Hope that helps

Posted by: kenshapiro2002 Aug 5 2009, 09:13 AM

Thanks. So do I look for 12 volts between the two contacts on the switch as the brake is depressed?
Ken

QUOTE(kwales @ Aug 5 2009, 11:08 AM) *

Tried the brake light switch?

It's down in the pedal cluster/ cover plate area and it actuates off the brake pedal. Use a VOM with a continuity setting to check. If the switch doesn't trip when the brake pedal goes in and out, there's yer problem.

Hope that helps


Posted by: type47 Aug 5 2009, 10:03 AM

QUOTE(kenshapiro2002 @ Aug 5 2009, 07:13 AM) *

So do I look for 12 volts between the two contacts on the switch as the brake is depressed?


I would not think so. The switch would simply close the circuit allowing the current to flow to the wires to the lights so there should be 12 V between the wires leading to the two terminals on the switch, that is, if you put a Voltmeter across the terminals while the wires are still connected, I would expect to see 12 V. If you put a V'meter across the terminals with the wires disconnected, I would expect to see 0 V as there is no voltage generated by the switch. I would think you would want to measure the voltage between the terminal on the switch that has the wire going to the lights and a chassis ground. That would tell you if you would have current to the light sockets.

Posted by: geniusanthony Aug 5 2009, 01:19 PM

Between ground and 1 side of the switch you would see 12v all the time, between the two sides of the switch would show 0v or zero difference of potential.. with the switch depressed you would then see 12v ground to out-side of switch. Continuity is the best check to see if your switch works. Same with jumping the two leads, bypassing the switch as you troubleshoot. make sure there is voltage before the switch though. After that is found to be true you can find if there is a break after the switch circuit.

Posted by: kenshapiro2002 Aug 5 2009, 01:21 PM

Thanks.
Ken


QUOTE(geniusanthony @ Aug 5 2009, 03:19 PM) *

Between ground and 1 side of the switch you would see 12v all the time, between the two sides of the switch would show 0v or zero difference of potential.. with the switch depressed you would then see 12v ground to out-side of switch. Continuity is the best check to see if your switch works. Same with jumping the two leads, bypassing the switch as you troubleshoot. make sure there is voltage before the switch though. After that is found to be true you can find if there is a break after the switch circuit.


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