Am I electrically illiterate?

C.Berry

C.Berry

Bad News
Joined
Aug 10, 2008
Location
Blacksburg, Va
Ok so I've considered myself a decent shade tree mechanic since my first 4x4/ vehicle I've managed top end rebuilds, standard r&r on 72-98 gm engines and even some fabrication on trail rigs in the past! But I've recently discovered that the electrical issues in my 94 gmc are not making sense is it possible im electrical retarded or why doesn't it come together? I've tried reading on electricity and had people basically demonstrate it and I still suck Terribly any help or suggestions?
 
Some people may be electrical illiterate, but I think you could teach yourself, just like learning a new language.

Look for a factory wiring manual on eBay. You can get printed books or CD. Factory manuals are 10000 times better than the Haynes or Chilton crap. It'll usually tell you exactly where splices and grounds are, and usually break the wiring down into simple systems. Using a factory manual would be like finding your way around downtown Charlotte with a Charlotte map not a map of the eastern seaboard.

Get some good wiring manuals, and pick a simple circuit like the horn and study it til you understand how everything works, then start looking at more complex circuits til you understand them.

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I've been around electrical stuff for a long time. I start doing house wiring when I was 13. First light I wired didn't work but I figured it out. When I was in my late teens I start working in an appliance store as a delivery boy. Owner had me fixing appliances before long including televisions. Mostly tubes back then with transformers, resistors, capacitors, and diodes. Went to Magnavox's factory school when transistors replaced the tubes. My point is newer vehicles can be really difficult to diagnos. Yes I can change out the bad part but which part? This forum is great cause there are some really great people out there that will share on any subject. I liked the old Motor Repair Manuals because they told how components worked and how to repair them. Do not beat yourself up electrical systems have gotten very elaborate and complicated. I put up with some things not working properly because I can't fix them( I can't figure out which part is bad). When I became frustrated with the A/C on my 01 Suburban which had sensors in the headliner, dash, and grille I installed a relay with a toggle switch to turn on compressor.
 
moldman05 said:
I've been around electrical stuff for a long time. I start doing house wiring when I was 13. First light I wired didn't work but I figured it out. When I was in my late teens I start working in an appliance store as a delivery boy. Owner had me fixing appliances before long including televisions. Mostly tubes back then with transformers, resistors, capacitors, and diodes. Went to Magnavox's factory school when transistors replaced the tubes. My point is newer vehicles can be really difficult to diagnos. Yes I can change out the bad part but which part? This forum is great cause there are some really great people out there that will share on any subject. I liked the old Motor Repair Manuals because they told how components worked and how to repair them. Do not beat yourself up electrical systems have gotten very elaborate and complicated. I put up with some things not working properly because I can't fix them( I can't figure out which part is bad). When I became frustrated with the A/C on my 01 Suburban which had sensors in the headliner, dash, and grille I installed a relay with a toggle switch to turn on compressor.
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That's why I say ignore the Haynes and Chilton books. If you truely want to fix your own car, find and buy the factory manuals, or subscribe to alldata or Mitchell, who copy factory manuals. The wiring diagrams are much better, and the factory repair manual has step by step flow charts for diagnosis. It's usually as simple as "check wire X at connector Y, terminal Z for voltage. If >5v go to step 7 if <5v go to step 13." You work through the flow chart til it tells you which part to replace.

I've been a mechanic for 16 years and I've only seen one time the factory manuals flowchart wouldn't diagnose the problem, I was at the Ford dealer and working on the power sliding door on a Windstar. I had to call the tech hotline Ford has for dealer techs and even they were stumped for a while, they eventually sent out a field engineer who figured out it was a faulty module.

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Thanks for response for instance I can hook up fog lights and they work fine but trying to figure out electrical issues on this 94 gmc is nuts my alternator went out on me yesterday bought a brand new one not refurb and drive home fine go to leave gain get down the road and electrical flicks and burb dies got a code 75 last week looked it up it said broke wire to egr or bad egr well my egr is new also! When I start the burb it'll high rev for 20 seconds then dash clicks and power windows stop working and it runs like crap thT happens often and random I've went over wires and seen non broke. Or bad I'm lost
 
Quite often you will hear check the grounds. I believe there is a braided non insulated ground cable near back of passenger exhaust manifold. I had one corrode and break. You can verify grounds with load on battery by seeing if there is voltage between the battery negative post and a good engine ground point. The more volts you have the worse the ground cables. You may have less than a volt which is the loss or resistance in the cables. Check with load on battery such as Lights, A/c , windows .
 
Powertrain diagnostics and basic understanding of DC go hand in hand, but it can still be a challenge. I'd take a look at some of the base scanner danner testing videos on you tube. If you can tell me exactly what systems your having issues with I can print diagrams and give you some base testing.
(You have already done so above, I just grazed through the post)

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Damn Edison and his DC shenanigans. . :shaking:
 
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