HELP!! '83 GMC Electrical Problems
Question:
I agree Remove the fuse and install a fusible link. I have seen problems with the alternator top adjusting bracket losing ground on this setup. The negative battery cable attaches to this bracket I would clean a few bolts to the water pump and intake that attach to this bracket. also move the cable to another hole in the bracket Also if your output wire (big red wire on the back of the alternator) from the alternator becomes open between the battery the voltage can rise to over 90 volts. So check at the starter as Mike had mentioned. also make sure that body ground is ok check the small wire off the battery negative cable then check the strap at fire wall to the transmission. Here is a speed secret use a good pair of jumper cables while the vehicle is acting up. hook to battery negative then to the alternator case watch the voltmeter, if not results move the negative cable to the fire wall if still no improvement jump positive battery cable to alternator output. Repair any circuit that improves with the jumpers. My bet is that the output wire is feeding the battery threw the cab instead of a strait shot to the battery via starter positive battery cable. Bob Anderson. Anderson’s Auto Repair 30 years experience ASE Master Mechanic. (SAE) J1930 translation Automotive Technician. 
When you fix it please post it to Http://buymycar.org/tech.html If you need more help I can supply you with a wiring diagram. – Hide quoted text — Show quoted text – > I have a ‘83 half ton 4X4 with a 305 with a intermittent electrical > problem. > The problem began when my son jump started the truck’s dead battery. > When he connected the cables, he saw a curl of smoke near the > firewall. The fuseable link had burnt. The link appears to be the > one leading down into the fuse block. > I replaced the fuseable link with an ATC fuse holder and 30 amp fuse. > Trickle charged the battery and everything was fine for a few days. > Then my son reported the electric windows going up and down twice the > speed they normally do. Looking at the voltmeter showed the needle > was pinned out past 18 volts. After shutting the truck off, it would > not start again. The 30 amp fuse where the fuseable link was had > blown. > Replaced that fuse and the truck started up again, voltmeter normal. > This problem appeared again so I decided to replace the alternator. > Same story. The truck may run OK for a couple of days then the lights > get real bright indicating no regulation on the alternator and the 30 > amp fuse is blown again. > Any ideas??? > Many thanks in advance. > Randy
Response:
>This problem appeared again so I decided to replace the alternator. >Same story. The truck may run OK for a couple of days then the lights >get real bright indicating no regulation on the alternator and the 30 >amp fuse is blown again.
For starters, get rid of the fuse and buy a piece of fusible link to fix the blown one instead. A fuse will not carry the current that a fusible link will, no matter the rating. Have the alternator output checked. Sounds like he may have hooked the jumper cables backwards and fried the rectifier bridge in the alt. Big Daddy ICQ#6342575 ASE Master Auto Technition Chevrolet Certified Master Tech.
Response:
Randy… I had a problem like this last week where the voltmeter would peg off the chart at times. I checked all of the links and fuses and the alternator (which you replaced) and could find no problems. The culprit ended up being a corroded connection inside the splice from the starter soleniod. After cutting it apart and repairing, the truck runs great again. Mike McKenna 83 Chevy 4×4 on a 78 Suburban frame and axles (corporate full floating rear, DANA 44 front 4.10 gears)
– Hide quoted text — Show quoted text -> I have a ‘83 half ton 4X4 with a 305 with a intermittent electrical > problem. > The problem began when my son jump started the truck’s dead battery. > When he connected the cables, he saw a curl of smoke near the > firewall. The fuseable link had burnt. The link appears to be the > one leading down into the fuse block. > I replaced the fuseable link with an ATC fuse holder and 30 amp fuse. > Trickle charged the battery and everything was fine for a few days. > Then my son reported the electric windows going up and down twice the > speed they normally do. Looking at the voltmeter showed the needle > was pinned out past 18 volts. After shutting the truck off, it would > not start again. The 30 amp fuse where the fuseable link was had > blown. > Replaced that fuse and the truck started up again, voltmeter normal. > This problem appeared again so I decided to replace the alternator. > Same story. The truck may run OK for a couple of days then the lights > get real bright indicating no regulation on the alternator and the 30 > amp fuse is blown again. > Any ideas??? > Many thanks in advance. > Randy
Response:
I have a ‘83 half ton 4X4 with a 305 with a intermittent electrical problem. The problem began when my son jump started the truck’s dead battery. When he connected the cables, he saw a curl of smoke near the firewall. The fuseable link had burnt. The link appears to be the one leading down into the fuse block. I replaced the fuseable link with an ATC fuse holder and 30 amp fuse. Trickle charged the battery and everything was fine for a few days. Then my son reported the electric windows going up and down twice the speed they normally do. Looking at the voltmeter showed the needle was pinned out past 18 volts. After shutting the truck off, it would not start again. The 30 amp fuse where the fuseable link was had blown. Replaced that fuse and the truck started up again, voltmeter normal. This problem appeared again so I decided to replace the alternator. Same story. The truck may run OK for a couple of days then the lights get real bright indicating no regulation on the alternator and the 30 amp fuse is blown again. Any ideas??? Many thanks in advance. Randy
