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Electrical Issues


Active Member
Know it's the wrong forum for this. Here's what I got I recently purchased a 1987 d100 with 118k original miles. It has been parked for many many years in a pole barn with serious electrical issues. It has power windows power locks an cruise control.318 with carb . I got the windows power locks an cruise working again. Got ac working Then it had charging issues got that resolved..wiring problems. Next it developed a vacuum leak at intake at egr valve crossover. Sprayed some we 40 on intake an found leak an changed intake gaskets. Prior to changing intake gaskets temp gauge was working...after changed gaskets on running like a top now....no temp gauge now.. Not the temps sensor it has 2 wires. The temp sending unit has 1 wire question is ...can I disconnect sending unit and ground that wire turn switch on shouldn't it peg the gauge in the hot position. Would that indicate a bad sending unit.. Next question can I take my meter an check wire for continuity. Put one test lead in plug for sending unit ground the other turn switch on an see what the reading is. Would that tell me if the wire going into wirng harness is good back to the gauge. While I was replacing intake gaskets . I went ahead an replaced water pump.. thermostat..heater hoses.. upper an lower radiator hoses...an done away with that air pump crap too an all associated....between gettin rid of that smog pump a new 2.5 in dual exhaust it put more pep in its step. With them wires being moved out of the way to replace to replace intake gaskets wonder if it broke a wire inside the insulation.....them wires are kinda stiff after all they 33 yrs old. I should be able to check that wire with my meter...any ideas


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Staff member
I would definitely check continuity on the wires in question. However, you will need to check just the wire which means you will likely need an extended lead for your multi-meter. But I would definitely start there.

As for the sending unit, if it's cheap, I would just toss one in to see if it fixes the issue. If expensive, then I would see if I could find the information for that sending unit to ohm it out to see if it is reading temp changes correctly.


Staff member
Armed Forces
The only thing to keep in mind with a continuity test is; it wont tell you if the wires are fractured. sometimes fractured wires can erratic issues, essentially when it comes to signal.


Active Member
Well , got that sending unit changed out ...think it was a loose connection at the stud on the sending unit anyway, plus it was all rusted an corroded so as I put a jumper to ground an had to scrape connector to get ground to check gauge ...an it worked. Went ahead an put new sending unit in anyway...cleaned connector an crumpled the connector for tighter fit..back working now....hold on not so fast...now it has some kind of heater motor issue....no wonder it was parked ALL them years...from what I've read 86-90..was plaqued with electrical issues...mainly arriving from poor connection of wireing harness at the fire wall connector due to oxidation an corrosion...so let's see...got power locks working...cruise control working..
Power windows working...fixed charging system...water pump..hoses new belts...intake gaskets...oh can't forget windshield wipers motor...that was a challenge come to find out that wiper motor is mounted on rubber grommets..fuse was good power at motor connector....motor checked good....come to find bad ground...all them electrical gremlins....so far from what I've read that is some of the electrical issues along with the fire wall connector....poor ground .....so gonna start the search again fuse ..switch ...heater resistor..
blower motor...check the ground too...thats a Saturday project

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