No low beams, high beams or instrument illumination... Help!

[AugustneverEnds]

Well I am mighty stumped. I have taken my interior apart this winter to deep clean and remove all previous aftermarket add-ons, alarm (what a mess :tantrum:), cruise control, back-up camera, and radio head unit (all non-functioning). The good news is the car starts, runs and is charging properly. The bad news is neither low or high beams will work and the instrument cluster is not lighting.

I replaced the printed circuit for the instruments and all gauges are working beautifully and I replaced all of the bulbs with LEDs except the charging system warning lamp. With the old printed circuit several gauges were inoperative but it was lighting up. Now it's the other way around. Not sure what to look at or do. :hmm: The side marker and tail lights are working so probably not the lights master switch.

Before I began my project my low and high beams were working. I wanted to repair the ground terminal on the high beam relay as the wire was barely hanging on to the terminal. Now when I try to turn the beams on I get nothing, no lights or click from the relays. I can jump the relay and get the lights to come on. Like this:40822

I also jumped the blue wire and the brown/blue wire at the light master switch and still got nothing so that should mean the switch is ok. I have the DMCH switch just for reference.

The only anomaly I think I noticed is that the schematic I am using 40823 has a blue/slate wire going from the high beam relay to the dip switch but I see a blue/red wire that the schematic doesn't have at the dip switch and no blue/slate wire. 40824

Whew!!! What a long post, thanks for reading this much and for any ideas

[Jonathan]

Is your rheostat plugged in? IIRC, it needs to be to get the instrumentation lights to come on.

[Gregadeth]

Did you check fuses? 8, 14 and 15

[David T]

Did you check fuses? 8, 14 and 15

Did you touch any of the plugs going to the steering column? The power for the headlights goes in and out of the dip switch on the turn signal switch.

[AugustneverEnds]

Is your rheostat plugged in? IIRC, it needs to be to get the instrumentation lights to come on.

Ahha!!! No rheostat plugged in at the moment, I have the center console out. Hope this is the answer, I will test it tomorrow.

[AugustneverEnds]

Did you check fuses? 8, 14 and 15

Fuses are good, the lights come on when the relay is jumped so power has to be going through the fuses. Thanks tho

[AugustneverEnds]

Did you touch any of the plugs going to the steering column? The power for the headlights goes in and out of the dip switch on the turn signal switch.

Hmmm I may have, something new to check tomorrow. I will have a look tomorrow and see.

[Bitsyncmaster]

The ground wires on that front relay bank can go bad and cause the relays to not get control voltage. It would be rare the problem is the first relays (headlight) but when one of the grounds goes bad that usually stops the rest of the relays in that bank to stop working.

So with an ohm meter you can check those relay ground pins for less than one ohm to ground.

[AugustneverEnds]

The ground wires on that front relay bank can go bad and cause the relays to not get control voltage. It would be rare the problem is the first relays (headlight) but when one of the grounds goes bad that usually stops the rest of the relays in that bank to stop working.

So with an ohm meter you can check those relay ground pins for less than one ohm to ground.

Thank you sir, will do. If I ground each relay separately, for testing, each one should work fine? Or do they need to be grounded to the bundle they presently are?

[Bitsyncmaster]

Thank you sir, will do. If I ground each relay separately, for testing, each one should work fine? Or do they need to be grounded to the bundle they presently are?

The OEM wiring runs from the common ground with one wire to the first headlight relay ground pin. Then it puts another ground wire in that relay pin to the next relay ground pin. This continues for each of the front bank relays. That way to wire is normally called a "daisy chain". What I have found is those two wires in one pin tend to just roll the pin over each wire and age oxidizes the connection. I would guess about 10 owners have found this problem. So I made up a new "ground buss" that uses one wire terminal crimps and then joins the separate wires feeding back with one wire to the ground point.

[AugustneverEnds]

The OEM wiring runs from the common ground with one wire to the first headlight relay ground pin. Then it puts another ground wire in that relay pin to the next relay ground pin. This continues for each of the front bank relays. That way to wire is normally called a "daisy chain". What I have found is those two wires in one pin tend to just roll the pin over each wire and age oxidizes the connection. I would guess about 10 owners have found this problem. So I made up a new "ground buss" that uses one wire terminal crimps and then joins the separate wires feeding back with one wire to the ground point.

Now things are starting to make sense! My relay bank is wired to ground as you describe it, I didn't know that was normal. It looked like one of the previous owners doings, sloppy and from the looks of it there has been some soldering repairs done in the past. The chain starts at the low beam relay and there is a yellow wire from the fan relay to the ground bundle. I guess at some point someone replaced the ground wire and didn't bother to use black wire. Are you selling your ground buss unit? I'd be interested

[Bitsyncmaster]

Now things are starting to make sense! My relay bank is wired to ground as you describe it, I didn't know that was normal. It looked like one of the previous owners doings, sloppy and from the looks of it there has been some soldering repairs done in the past. The chain starts at the low beam relay and there is a yellow wire from the fan relay to the ground bundle. I guess at some point someone replaced the ground wire and didn't bother to use black wire. Are you selling your ground buss unit? I'd be interested


Fan Fail, $94
Electronic fused Fan Fail, $114
Dome unit, $88
RPM relay, $83 with your old unit
Fan relay, $77
Blower relay, $72
Head Light relay, $72
Hot Start relay, $66
Pair of window switch LED boards, $20, $25 installed, requires the new DMCH switches.
Idle ECU, $138 with your old unit. I have 11 pin units also for $150 with your 9 pin unit returned.
LED AC panel, $110. Your choice of blue or green backlighting.
Front Relay Bank Ground Buss, $15. $10 if combined with another product.

Prices include shipping to lower 48 states

[AugustneverEnds]

Update: Nothing to report, I was at work late yesterday and couldn't go test things on the car. Hopefully today.

@ Bitsyncmaster: I would definitely like to buy your ground buss unit. Do you accept Paypal?

[Bitsyncmaster]

Update: Nothing to report, I was at work late yesterday and couldn't go test things on the car. Hopefully today.

@ Bitsyncmaster: I would definitely like to buy your ground buss unit. Do you accept Paypal?

I PM ed you my email and paypal address.

[AugustneverEnds]

After many late days at work and a cold snap, finally installed Bitsyncmaster's ground buss and got my lights to work when the high beams are switched from the dip switch. Still no low beams. Does anyone have a diagram of the wires going to the dip switch? It's the only thing I can't be sure about.