Good Starter, Brand New Battery, Won't Crank

JohnRGood

I have a 1988 GMC Sierra 1500, that recently after running with no problems at all, won't turn over at all. We know for a fact the starter is good, and to be safe, we had the starter itself tested, and sure enough, its good. The battery that was in it was bought in late 2018, but out of curiosity, we bought a brand new battery and still nothing. Dash lights come on and the over head light works, brake lights work, headlights, etc. The only noticeable thing is when I turn the turn signal on, the dash lights and everything else start flickering and flashing. Jump starting the truck also doesn't help at all. I want to see if anyone knows what the problem may be before I give up and have it towed to a mechanic.

thecardoc3

It really doesn't work that way. What was tested and proven to be wrong with someone elses car/truck doesn't mean anything with regards to what yours is doing. With the right tools, knowledge, and experience, a tech will test and prove what is going on efficiently. Even looking at your description one has to allow for the possibility of you describing one problem, or more than one problem. Someone can say something like "check the grounds" which doesn't actually mean find them, take them apart, clean them up and re-attach and see if it fixes the car. It means try to operate the failed system and measure the voltage drops across them.

JohnRGood

thecardoc3 said:

It really doesn't work that way. What was tested and proven to be wrong with someone elses car/truck doesn't mean anything with regards to what yours is doing. With the right tools, knowledge, and experience, a tech will test and prove what is going on efficiently. Even looking at your description one has to allow for the possibility of you describing one problem, or more than one problem. Someone can say something like "check the grounds" which doesn't actually mean find them, take them apart, clean them up and re-attach and see if it fixes the car. It means try to operate the failed system and measure the voltage drops across them.

I understand the concept that cars problems will be different with each car, I'm not expecting someone to know indefinitely what is wrong with my truck. Just looking to see if someone who's had a similar experience with a similar vehicle can offer some help. After all, I did list the trucks make, model, and year.

thecardoc3

As I explained, it really doesn't work that way. Over the years I have diagnosed and repaired numerous similar trucks with no crank issues. The most common causes you state have already been ruled out and that is the battery and the starter. I can think of a couple dozen that turned right around and after we were told it couldn't be one of them that was in fact one of them...... From there it could be one of the battery cables, or the chassis ground strap that goes from the right front of the frame to the engine. It could be the ignition switch or it's connector or wiring. The neutral safety switch or it's connector or wiring. The engine be itself might be locked up. I've even had some where the transmission front pump locked up, or a belt driven accessory (alternator, AC compressor) preventing the starter from turning the engine. I can toss out a few more obscure causes and anyone of them could be right which doesn't mean that going and trying to check them is a reasonable effort. Trying to fix this by anything other than using a proper testing routine can get lucky or waste a lot more time and money.