Author Topic: ELECTRICAL ISSUE...  (Read 4186 times)

Offline SLO 85 GT

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ELECTRICAL ISSUE...
« on: May 15, 2007, 10:15:27 AM »
I have a 1987 Suburban and i just recently started driving it again since the race season has started...Now my issue is: when i turn on my headlights i lost my running lights & dash lights and just have headlights. I looked in my repair manual and it says to replace the light switch but after further investigation i found a blown fuse for the taillamps(25 amp spade) after i replace it and drove the truck for 5 mins and the lights blew out again >:anyone have any exp in this issue? Does that headlight switch has a breaker in it and should i have replaced it instead of the fuse..


Thanks
Darrin
« Last Edit: May 15, 2007, 10:17:16 AM by SLO 85 GT »

Offline VileZambonie

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Re: ELECTRICAL ISSUE...
« Reply #1 on: May 15, 2007, 02:31:13 PM »
If you are blowing the fuse you probably have a short to ground. - Unplug the rear lighting harness connector and replace the fuse. See if it blows out again. This is kind of a redneck way to do it but I doubt you have a lot of electrical diagnostic tools so start with that.
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Offline Lt.Del

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Re: ELECTRICAL ISSUE...
« Reply #2 on: May 15, 2007, 08:39:54 PM »
Do what Vile said, you can  narrow your search then.  Look for any bear wires in the wiring harness, up under the truck, follow the wires back.   
This happened to me once, where the wires were chewed and bear at a specifica place and grounded out, blowing fuses....dang squirrels love chewing on wires.   I bought a trap and took 23 squirrels to the other side of the interstate, about 7 miles away. 

Offline SLO 85 GT

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Re: ELECTRICAL ISSUE...
« Reply #3 on: May 15, 2007, 08:47:00 PM »
If you are blowing the fuse you probably have a short to ground. - Unplug the rear lighting harness connector and replace the fuse. See if it blows out again. This is kind of a redneck way to do it but I doubt you have a lot of electrical diagnostic tools so start with that.


 I hate to sound stupid but where will i find the rear lighting harness?( Under the truck or?) Plus when i put another fuse in their the other day i saw some smoke coming from the dash before the fuse blew and the dash lights went out.

« Last Edit: May 15, 2007, 11:26:02 PM by Captkaos »

Offline Captkaos

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Re: ELECTRICAL ISSUE...
« Reply #4 on: May 15, 2007, 11:27:11 PM »
look under/inside the drivers side frame rail.  Or under the drivers taillight.

Offline VileZambonie

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Re: ELECTRICAL ISSUE...
« Reply #5 on: May 16, 2007, 03:55:23 PM »
Yikes! Be c areful - don't put in fuses with higher ratings or just keep putting them in. If you don't find the problem with your rear harness somewhere let us know.
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Offline SLO 85 GT

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Re: ELECTRICAL ISSUE...
« Reply #6 on: May 17, 2007, 08:01:52 AM »
Ok ;D Will do. I have to get this repaired soon.

Offline joesgarage71

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Re: ELECTRICAL ISSUE...
« Reply #7 on: May 17, 2007, 08:17:52 AM »
 You might want to be looking under the dash where the smoke was coming from first.
 Steve
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Offline Lt.Del

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Re: ELECTRICAL ISSUE...
« Reply #8 on: May 17, 2007, 09:07:22 AM »
Have a fire extinguisher handy, really.  Smoke means fire/spark.
If you don't have voltmeters and such, try putting in a fuse at night.  Ensure all your garage lights are out.  If you have a camcorder or something, I'd records up under the dash, lay it down on the floor board pointing up or something.  Have someone turn the ignition key while you are on your back and looking up.  Turn on the headlight switch. You are bound to see something and therefore can pinpoint the general area if you see a spark...chances are a wire has been rubbed and stripped a little and is grounding out.  When you say you drove it about 5 miles and it then blew, i would believe you probably hit a bump or something.  You may have to jiggle the wires and stuff while looking up under the dash.  If it is rubbing on metal, you will eventually see it spark. 

And as stated earlier, do not use a higher amp fuse in that circuit. If you do, you will be sorry--the wires are rated at a certain amperage and if by short-circuiting, more amps are drawn on that circuit, serious melting of wires and componenst/switches will result. That is if you are lucky.  If you are unlucky, your entire truck will go up in flames.  In fact, when doing this test, do it outdoors so your garage/home wont burn up.

If you are near a salvage yard, I'd get another head light switch just in case.  The switch is grounded where it meets the metal dash.  If the guts of the switch are bad or stripped, it may cause the circuit to ground out, i presume. If it still blows, atleast you would have ruled it out.

The switches are very easy to replace.  There is a little push button on the side of the switch up under the dash that you must push in to pull the knob stem out.  Then just unscrew the switch.

Offline SLO 85 GT

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Re: ELECTRICAL ISSUE...
« Reply #9 on: May 19, 2007, 07:38:55 AM »
I did replace the fuse with the 25 amp rating that was to be used and i did pick up a new light switch from Pepboys yesterday and i have a volt meter that i use to track electrical issues with my race car...I'm gonna try the lights out deal today when i get home from work..



Thanks Guys ;D

Offline CruzinHigh

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Re: ELECTRICAL ISSUE...
« Reply #10 on: May 19, 2007, 12:11:37 PM »
I recently rewired my entire rear subharness for the taillights.

The system has a few splices in there that are factory made, and frankly, I can't believe mine lasted as long as they did.  Crimped and soldered and then simply covered with tape, they are subject to corrosion and chaffing over the years and might be rubbed through.

Maybe your problem is under the dash as you've developed here, but here's a pic of the rear harness connections just for your knowledge.   If those are rubbed through and touching ground, POOF.

Mike Carter
1986 Chevy K-10 4x4

8" lift project on the way soon!

Offline SLO 85 GT

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Re: ELECTRICAL ISSUE...
« Reply #11 on: June 07, 2007, 11:17:54 PM »
Well guys this is was we found. I needed a new headlight switch( MELTED) Replaced the wiring from both front marker lights all the way under the dash( MELTED)..I now have truck lighting as well as trailer lighting...I really needed the trailer lighting due to towing back from the Dragstrip at night...



Thanks For the help guys!!! ;D
« Last Edit: June 10, 2007, 12:11:32 AM by SLO 85 GT »

Offline Lt.Del

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Re: ELECTRICAL ISSUE...
« Reply #12 on: June 09, 2007, 10:00:13 PM »
Glad you got it figured out.  The fuse should've fried well before the entire circuit and switch melted. Must've had one heckofa short.