Suburban lost instrument panel lights and taillights

[springcreekranchusa]

My 99 Suburban had no lighting problems with my utility trailer, but with my boat trailer hooked up, I got no instrument panel lights or tail lights when I turned on the headlights. Now, even without the boat trailer hooked up, I get the same results. I can't find any blown fuses in the interior fuse box or in the fuse and relay box in the engine compartment. (Brake lights, turn signals, flashers, and everything else works normally. Just the tail lights on both the Suburban and trailer and the instrument panel lights on the Suburban are inop.) What is the fix for this?

 

[Skiuseme]

Re: Suburban lost instrument panel lights and taillights

Hait to Say it but you might want to start by Checking some of your grounds in the Truck. There should be about 200 of them

 

[jimchere]

Re: Suburban lost instrument panel lights and taillights

I'll take a quick stab at it without specifics....and no guarantees that this is the right approach.... First you probably got a problem with your boat trailer wiring and you need to ring that out. That probably cooked a relay in your headlight circuit when you connected the boat trailer with the hosed up wiring to your truck. Remove negative cable from battery. Open up the relay/fuse box under the hood and you'll see the relays, the silver or black square (about 1") box things. Pull them out one at a time (or if they're labelled then only the headlight ones) and give them a firm (not gentle, but not REAL hard) taps on something solid and then reinstall. Try a few times. Hook up battery and see what happens then. Other than that, you're going to need a wiring diagram and multimeter to chase it down.

 

[Kenneth Brown]

Re: Suburban lost instrument panel lights and taillights

I know you are gonna think I'm crazy but it probably is the fuse. Sometimes they will burn on the very edge and you can't see it.

 

[springcreekranchusa]

Re: Suburban lost instrument panel lights and taillights

Thanks for the replies. I have discussed the problem with several other people and one of them suggested that some GM vehicles have been known to exhibit this type of behavior. One of the possible causes is a burnt out fusible link, which is most likely located somewhere other than with the rest of the fuses. If that's the case, I would need to find and replace that, and then also install some sort of aftermarket electronic control box that tricks the Suburban into not knowing how much juice it's putting into the trailer light harness. Without this aftermarket box, the stock system sometimes won't operate correctly because of the extra power drain of the trailer lights.<br /> I honestly don't think it's a ground problem because the turn signals, brake lights, and hazard flashers all work correctly, and I never had this problem with my utility trailer. It could be there is a higher power draw with the boat trailer because of the running lights that the utility trailer doesn't have. <br /> I don't think it's a headlight relay because the headlights also operate correctly. It evidently has something to do with the headlight switch circuitry which also controls the instrument panel lights and tail lights. I am looking into getting a GM service manual that would show me the wiring schematics of the Suburban to start chasing down the power supplies to these systems.

 

[springcreekranchusa]

Re: Suburban lost instrument panel lights and taillights

Okay, I'll eat my crow now and apologize for my prior remarks. Yesterday I would have bet a fair amount that there were no blown fuses. Today, I found a blown Park Lamp fuse that when replaced, fixed everything. I guess I was so caught up in looking for something that said "instruments" or "gauges" that I couldn't see the forest for the trees. My apologies. <br /> Now, I just have to find the problem with the trailer wiring that caused the fuse to blow. Thanks again for the input.

 

[Kenneth Brown]

Re: Suburban lost instrument panel lights and taillights

<br /><br />I might have the solution to the other problem too. I have had 3 of the plug in adapters for trailer lights. On every one of them the truck side white wire (which is supposed to be ground) was actually back up lights. Of course the trailer side was ground, and whenever the truck went into reverse it would pop the fuse. It would only do this with my boat, I used trash trailer and it wouldn't blow it. I noticed that the trsh trailer was missing the ground wire. I messed around with a test light and shure enough, my supposed ground was back up lights.

 

[springcreekranchusa]

Re: Suburban lost instrument panel lights and taillights

Thanks for the heads up, Kenneth. I'll check into that.