78 short box 4x4 electrical problems please help - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Truck Norris · 07-07-2011, 03:38 PM

Hello all, I have a 1978 Chevy 4x4 Silverado and I'm having some electrical issues. My truck was stolen and stripped back in December among items taken were my door panels and power window and power lock switches. I found switches off a 79 at the junk yard and everything worked great for a couple weeks then suddenly no windows.. I tried to figure out why they didn't have power but no luck. I then spliced the power wire from the locks into the windows and again everything worked great for a few weeks then within a few minutes driver side lock quit then passenger then both windows. And I'm not sure if its related but the blinkers are not working right now either. Please any guidance would be very appreaciated, this has been a nightmare.

Restrorob · 07-07-2011, 06:11 PM

Being a 78, The first place I'd check is the wires going through the door jams. The wires tend to break after so long, I've repaired a few over the years.

As for the turn signals, A little more info on what their doing/not doing would be helpful....

Truck Norris · 07-07-2011, 07:13 PM

Thanks for the reply! I checked between the door jam on both sides and found only a very minor cracked wire on the driver side, could just a crack cause this? Everywhere I am able to test the wires for the windows and the locks everything is coming up dead.. The blinkers started acting up this last time I lost power to the windows and locks. They will only blink one or two times when you first click it on then nothing. I also noticed my amp gauge showing low then high and all over at that time. Thanks for your help, back to the garage..

Restrorob · 07-07-2011, 09:01 PM

Quote:

Originally Posted by Truck Norris

They will only blink one or two times when you first click it on then nothing. I also noticed my amp gauge showing low then high and all over at that time.

The above sounds like it could be one of two things, A bad flasher or a short in the electrical system which is probably why the windows/lock quit.

Swap the four way flasher with the turn flasher and see if that solves the signal issue.

As for the jam wires, The wire strands can break inside the insulation. Physically looking at them they can appear to be good but actually have a open circuit, Test for power at the fuse panel going to the door and ground from the door to the body/frame. If you have power at the panel and none in the door disconnect the battery and test each wire with a multimeter set on ohm's scale from the door/lock switch to the fuse panel and door switches on the right side.

It's easier done than said but hopefully you get the idea.....

lunchbox99 · 07-07-2011, 11:54 PM

it sounds to me like you might have a ground issue, i would start with the basics, clean up all the grounds with a wire brush and make sure they are tight, if that doesnt fix it bust out the ohm meter and find the end of the power supply.

Truck Norris · 07-08-2011, 04:48 PM

Sounds a Little over my head but I'm learning as I go. Thanks for taking the the time to help!

07-07-2011, 03:38 PM	#1
Truck Norris Registered User Join Date: Jul 2011 Location: Spokane Wa Posts: 4	78 short box 4x4 electrical problems please help Hello all, I have a 1978 Chevy 4x4 Silverado and I'm having some electrical issues. My truck was stolen and stripped back in December among items taken were my door panels and power window and power lock switches. I found switches off a 79 at the junk yard and everything worked great for a couple weeks then suddenly no windows.. I tried to figure out why they didn't have power but no luck. I then spliced the power wire from the locks into the windows and again everything worked great for a few weeks then within a few minutes driver side lock quit then passenger then both windows. And I'm not sure if its related but the blinkers are not working right now either. Please any guidance would be very appreaciated, this has been a nightmare.

07-07-2011, 06:11 PM	#2
Restrorob The One And Only !!! Join Date: Jan 2007 Location: Hole in the woods Florida Posts: 4,567	Re: 78 short box 4x4 electrical problems please help Being a 78, The first place I'd check is the wires going through the door jams. The wires tend to break after so long, I've repaired a few over the years. As for the turn signals, A little more info on what their doing/not doing would be helpful.... __________________ 93 Jeep XJ 88 Buick La Sabra Toys; 88 TA-GTA in the works.... 97 GMC Ext. Cab 502 Crate 5 Spd......Sucks Gas But Haulz Azz ! The primary function of an Engineer is to make it difficult for the Fabricator and impossible for the Mechanic. *"Why go out preserved when you can go out beat up, worn out, sliding in sideways screaming, Holy Sh!t What A Ride" !!!*

07-07-2011, 07:13 PM	#3
Truck Norris Registered User Join Date: Jul 2011 Location: Spokane Wa Posts: 4	Re: 78 short box 4x4 electrical problems please help Thanks for the reply! I checked between the door jam on both sides and found only a very minor cracked wire on the driver side, could just a crack cause this? Everywhere I am able to test the wires for the windows and the locks everything is coming up dead.. The blinkers started acting up this last time I lost power to the windows and locks. They will only blink one or two times when you first click it on then nothing. I also noticed my amp gauge showing low then high and all over at that time. Thanks for your help, back to the garage..

07-07-2011, 11:54 PM	#5
lunchbox99 Registered User Join Date: Mar 2011 Location: Medford, Oregon Posts: 33	Re: 78 short box 4x4 electrical problems please help it sounds to me like you might have a ground issue, i would start with the basics, clean up all the grounds with a wire brush and make sure they are tight, if that doesnt fix it bust out the ohm meter and find the end of the power supply. __________________ 79' GMC stepside...the money pit! 355 aluminum partoit heads 2.02,lunati 268 flat tappet,comp roller rockers 1.6,hi-tech torque link intake(Jim McFarland),electric water pump,650 holley double pumper,msd 6al,msd street fire dizzy,doug's long tube headers(ceramic),3" exhaust(flowmaster 40)

07-08-2011, 04:48 PM	#6
Truck Norris Registered User Join Date: Jul 2011 Location: Spokane Wa Posts: 4	Re: 78 short box 4x4 electrical problems please help Sounds a Little over my head but I'm learning as I go. Thanks for taking the the time to help!

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