Electrical troubleshooting help please

[maxpanic]

So I helped a friend the other day pull a tahoe out of a pit in the snow at night. I had to pull it out up hill on an ice road. ended up putting chains on the Deuce to finally get that SUV out. Things seemed fine after about 2 hours of low gear spinning tires weaving back and forth. Probably should have put a couple of tons of rocks in the back to get better traction. Anyhow the Deuce drives me home, no problem. I park her and let her rest for a few days. I go out to start her up and when I turn on the electrical switch before starting, most of the instruments are not moving. especially the battery meter. I try to start her anyway but nothing. I pull the batteries and they measure about 2.8 volts. So I charge them up till they are about 11 volts each. put them in the truck. I wire up the positive, then the battery jumper from negative to positive between the batteries and then I put the negative/ground on the battery. I immediately hear a strong click/thud from the area of the starter. I disconnect the negative and connect it again. each time it does this strong click/thud. so I am thinking my solenoid on the starter must be messed up. I verified that my electrical was all off and that nothing was accidentally left on that could drain the batteries. Anyone have anything more definitive than my guess?

 

[porkysplace]

11 volts isn't enough charge they should closer to 13.9v . So you need to get a full charge first . Start checking grounds and connections while they are charging.

 

[cattlerepairman]

Unless you forgot to switch off the Acc switch or left the heater blower motor running, there is no reason why batteries should drain down, without another major defect. Check the battery cables, where they cross over the frame member; any chafing etc?

Once you get the engine started, check alternator output (voltage) directly at the alternator. It is a 24V system, so 26-28 V is about as much as it should put out. What I have seen happening is that the alterator puts out too much voltage (there is a regulator that can be adjusted). Because many trucks are only run short distances or for an hour or two, the batteries will survive higher voltage for a while. When you finally go for a long drive or operate the truck for a long time, the generator voltage cooks the batteries. They start bubbling out electrolyte and the cells die. You won't notice unless you shut the truck off or you go smell around the battery box for the characteristic electrolyte smell.

My two cents. I would not be surprised if adjusting alternator voltage and two new batteries were your cure.

 

[AN/ARC186]

It sounds like a solenoid/starter issue to me, sometimes they get hung up. I light tap(or a hard one, your call) can sometimes un stick things.

 

[Recovry4x4]

There is also a magnetic switch on the side of the block on some deuces. This will need to be checked too but only after you get the batts up to snuff.

 

[JH1]

Almost sounds like the starter solenoid on the starter got stuck on, and the starter was running, even though the little gear had retracted already. I think the starter solenoid launches a bar forward to connect the heavy 12V to the actual starter motor. Once you get off of the start button, it's supposed to retract away by spring pressure. If it happened to melt itself into the on position, it would have run down your batteries, as you say. Did you happen to hear a funny sound, like a free running starter motor? Did you notice your headlights dim or were you using them on the way home? I'm not a deuce wrench, but I've gotten greasy under one.
Jim

 

[cattlerepairman]

Any updates to this??

 

[maxpanic]

Thanks for asking. I went ahead and did the hammer tapping on the starter and solenoid. Didn't help. I think I can safely say it isn't a solenoid. I did some closer listening on the connection of the negative cable and it is clicking like a relay I think. so either I have a bad relay or a short to the relay near the starter. I really want to get someone to help by putting on the negative cable while I inspect up close and personal with the relay and starter. That should help me to narrow it down. Kinda tough to do with one person so I have a friend coming over on Monday to help out. Should have more to report by then.

thanks.

 

[m-35tom]

there is only a single wire to the starter relay coil. just take it off.

 

[Scarecrow1]

If It isn't powering something you left running then it sounds like a short somewhere. the fact that you hear a clunk coming from the starter to me indicates it is getting power even without you pushing the switch so I would just start with a volt meter and back track from the starter . Your switch may have shorted out like has been said ...............

 

[maxpanic]

Update on this. Turns out the sound wasn't coming from the starter after all, the clicking sound was coming from that general part of the engine bay though. the clicking was coming from the horn relay, the horn appears to have shorted. Anyone have thoughts on how/why those typically would short like that and cause the batteries to drain? Funny how the short must have happened after I parked her since I never heard the horn and I drained the air tanks so never heard a thing.

 

[cattlerepairman]

Horn activates via switched ground. It is permanently hot. One common cause is insulation defect of the horn wire where it exits the steering column, top or bottom. There should be a rubber plug in the bottom end to prevent this.

 

[m-35tom]

unless the selenoid coil itself shorted. bottom line is 40 plus year old stuff fails.

 

[swbradley1]

bottom line is 40 plus year old stuff fails.

Who knew?

 

[DUG]

unless the selenoid coil itself shorted. bottom line is 40 plus year old stuff fails.

Then I'm in deep chit cuz my truck is pushing 50.

OP - glad you got it figured out. Electrical is my least favorite troubleshooting topic.

 

[maxpanic]

unless the selenoid coil itself shorted. bottom line is 40 plus year old stuff fails.

Yeah, 40 year old stuff fails, but over time, like that, it should fail in a consistent way on locations that receive heavier wear than others.

 

[cattlerepairman]

No. Over time it fails in a consistent way at locations that need heavier lifting, more chit to be removed and take three times longer than the last failure you repaired!
Murphy has a woodland camo outfit, too.