Chasing down an electrical problem.

[Beefcake]

I have a new problem with my ¾ ton. I suspect it has something to do with my hazard circuitry. When I pull the hazard tab, nothing changes, I don’t get the blinking lights.

What is constant is the lights and gauges are all going crazy. My turn signals lights always say lit, The fuel gauge gets pinned down to empty when the brake peddle is applied.

Im not sure how the hazards work. But since they aren’t working at all, Id like to fix that first. What makes the hazards blink? Where is the box located? What does it look like? Im really hoping its something as simple as the (hazard box) malfunctioning.

thanks!

[MrGoodpliers]

I think that it's a flasher on the fuse panel. You know, one of those big things that plug into the panel? I don't know if it's the round one or the square one, though.

[fatfords]

The "flasher can" could be plastic or metal, round or square. There is one for the hazards and one for the turn signals. The hazard flasher is the one on the top of the panel.

You might check to see that your fuel gauge wire is hooked up to the panel correctly, and not to the brake light terminal on the panel. Should be in the top position, next to the hazard flasher can that you are looking for.

I can check my wiring diagram later this evening when I get home from work. Do all your turn signal lights stay on (both front & back, outside and the panel indicators)? It could be your column switch causing both the signal problem and the hazard problem.

Good Luck!

[Beefcake]

"Do all your turn signal lights stay on (both front & back, outside and the panel indicators)? It could be your column switch causing both the signal problem and the hazard problem. "

Yes, they do. I think your possibly right about the column switch... I followed the white wire which is activated by the brake up to the column. I didn’t tear into the column yet (it was getting late last night) but I noticed that the other wires returning from the column had continuity with the white wire. This makes sense if the hazards were on... -yes, no???

thanks for your help!

[fatfords]

"I followed the white wire which is activated by the brake up to the column. I didn’t tear into the column yet (it was getting late last night) but I noticed that the other wires returning from the column had continuity with the white wire. This makes sense if the hazards were on... -yes, no??? "

With that bit of information, I would "guess" that the hazard switch is in the "on" position and the hazard flasher is "stuck" on, also. I would try replacing the hazard flasher unit, as they are only a couple of bucks at the local parts store, or you might snag one out of your parts truck. If that doesn't fix the problem, take the steering wheel off and clean the connections on the signal switch and lubricate. Make sure the hazard switch has a positive "on" and "off" click when you move the switch.

Good Luck!

[72k5]

I know you said you want to fix the hazard light problem first, but it sounds like a bad ground might be part or all of your problem here. The gas gauge moving with the brake pedal is very likely caused by an inadequate ground. I would assure that the ground side of the truck is ok first. Accurate troubleshooting depends on a good ground in most cases, and can be a misleading and expensive waste of time and parts without it.

Use a length of wire a little longer than your truck. Attach it to the negative battery terminal and use it as the ground side of your voltmeter. Make sure the battery terminals are clean. I would clean them until shiny regardless. Fire up the truck, and turn on the lights and some electrical accessories. Probe around with the voltmeter to see if you get voltage on the engine or body parts. Check the engine, a number of spots on and around the dash, frame, head and tail light housings, and fuel tank if metal. Check any metal part that isn't moving that you see along the way. Anything over a volt or so indicates a problem in the connection somewhere between that part and the negative terminal of the battery. If you find nothing, prop the brake pedal down and check again, esp. around the dash, rear and tank.

Clean connections, or add wire as needed until the voltage goes away. Pickups often need to have a wire added to bridge the bed to the frame.

Doing this may be a waste of five minutes, or it may solve all or most of your problems if you find ground problems to correct. It is always the first place to start before beginning any serious electrical troubleshooting, and should be the main plan of attack anytime you see multiple problems start at the same time or you see things "going crazy".

Good luck.
Mike

[A.P.]

Like others said, check your grounds. I had a ground problem awhile ago and it was causing weird problems.
Here is a pic of the fuse box that some other member posted a while back, I don't remember who but they did a good job of labeling everything. Hope it helps.

A.P.

[A.P.]

This diagrams sure helped me track most of my problems. They are better then the ones I got in my Haynes repair book.

http://www.geocities.com/chevroletc1070/wiringdias.html

[Beefcake]

you guys are great! Ill let you know how it goes tonight.

[Beefcake]

I spent about 6 hours on that harness last night. I believe I have it narrowed down to the column. Kinda where I was 2 days ago, but I totally went throught the harness and replaced a lot of stuff the p.o. had done. Those wiring diagrams helped out a lot- thanks!!

Ill keep you guys posted if I find anything significant.

[Beefcake]

The p.o. did a ton of hacking on my truck. Between rewiring his radio, and installing a new ignition switch, there where plenty of problems. The turn signal switch was pretty worn on the column, and seemed to be missing some of contacts. I replaced the switch with the one in my ½ ton. That pretty much fixed the turn signals/ hazards. Except the brake lights didn’t work. That kinda stumped me, The rear taillights had voltage, the bulbs had continuity but no lights. Finally it hit me. The housing for the bulbs where so rusty that they couldn’t provide a good ground. So I replaced those with the ones on the ½ ton parts truck also. Everything works now!!

thanks for all your help guys!!

[A.P.]

Good job.


A.P.