I got my truck on the road about a month ago. It's mostly been reliable, except for the electrical system. About twice a week, it just won't start. There are two versions of the problem.

Version 1: Nothing happens when I turn the key. In EVERY occurrance of this, I have been able to start the truck with a remote starter switch connected at the solenoid. This led me to believe it was the ignition switch. I replaced the ignition switch. It still occurs occasionally.

Version 2: Very rapid clicking of the solenoid, accompanied by weak cranking or no cranking. This problem requires a jump start for help.

Before I ever drove the truck, I installed the following (related) new parts:
Battery
Battery cables
Ground strap
Main alternator wire

Since I've been driving it, I have slowly replaced the following:
Voltage regulator
Ignition switch
Alternator

I've also temporarily used a known good battery from another vehicle, with the same results.

Before I replaced the alternator, I had the system tested (on the truck) at Autozone. The old alternator tested bad at that time.

The only accessories I've used are the lights, wipers, and radio. Haven't used the heater/vent fan at all. No A/C.

Any ideas?

 

Do another load test with the new alt. My guess is the alt is not recieving the 12 volts to excit the field so it will start charging.


Is the alt reading 12 - 14 volts at the terminal while the engine is running?

 

I assume you mean at the BAT terminal on the alternator? I'll check that tonight.

What would cause it to not receive 12 volts? (Other than a bad wire) Voltage regulator?

 

If the field and stator wires were swapped, could it cause this problem?

I have another active post trying to verify the correct alternator wiring. No one responded the first time (a month ago), so I just guessed and it seemed to work.

 

Yes, a bad wire or connection. You mentioned that you replaced the regulator. I would say it is still good, but you never know. Its been a few years since I messed with the old Ford charging systems. I converted over to a one-wire alt.

Take it back to a shop that can load test the charging system. If you can check the voltage out on the back of the alt, do that yourself. I always take mine to a shop that actually rebuilds alts. They have the right equipment that will test your system.

 

Check your brake light switch. This one got me for a while. My brake lights would sometimes stay on without me knowing it and gradually would drain the battery down. I also once had to replace the thingamawhozit that is bolted to the radiator support frame. I found this was draining current. (Might be the voltage regulator? My mind drew a blank). With these simple wiring systems, it's not that hard to isolate what is drawing current. I did it with a multimeter and pulling something off watching for results.. that's how I found the thingamawhozit. The brake lights was dumb luck - I caught it at night grabbing something out of the bed of the truck.

 

How about the solenoid. It sounds to me like that might be responsible for some part of the problem. Good luck, John

 

That was going to be my guess. The "rapid clicking" is what made me think so.
If the solenoid is going bad, the truck won't start even with a new battery. Solenoids are not too expensive, I think I paid around $10.00 when i replaced mine.

 

I forgot to list the solenoid as one of the parts I have replaced. The rapid clicking would make me suspect it as well, but all testing has shown that each time this problem occurs, the battery really is weak/dead. Also, with a good solid jumpstart, it starts just fine.

Maybe the solenoid is a lemon and it's contributing, but I don't think it's the root cause.

 

Update on Problem #1 in my original post:

Today at lunch, problem #1 occurred. I hopped out with my remote starter switch, popped the hood, and the engine cranked right up. Then the truck started driving away in reverse! Fortunately my buddy was in the truck and stopped it, and no one got hurt.

Obviously when I parked the truck this morning, I left in in reverse, and the neutral safety switch did its job. But when I hooked up the remote starter switch at the solenoid, I bypassed it. So now I know that my neutral safety switch sometimes activates when it shouldn't, and that's what is causing problem #1.

I'll spend some quality time on problem #2 tomorrow, using your suggestions. Thanks for the help.