Solenoid or starter problem

1st find test light ck for power at starter on sol. small wire, you may need to tighten and clean all conn. at batt. and grounds on frame, take short wire to cross small wire to pos. wire on starter, if it starts an then starts some times from key afterthat replace starter or keep hot wire under seat for use later?

 

It sounds like a Starter Solenoid issue, if your Starter is original or hasn't been replaced in a long time, it's cheap insurance just to buy a replacement and be done with it.

Of course do check and clean your connections, but sounds like the Solenoid is on its way out.

 

I had the opposite way last week. Long story short. My starter kept on cranking even when I had the key removed. After a service call and a $1100 the starter still did the same. Turned out the starter relay got stuck and supplied continued power to starter. Relay was cheap, only $23. Ignition lock could be another issue.
But I agree, usually it's the starter if everything else seems ok.

 

Sounds like starter contacts are worn. Just buy a rebuild kit and replace it yourself

 

We usually replace both anyway when changing a starter. Those relays aren't expensive and it is cheap insurance.

 

Key on ---- > Starter relay (usually on firewall, or step box) -----> Magnetic switch on starter ----> starter solenoid

Is it a click or more of a clunk? Modern starters do not need the relay so on my trucks I bypass it for less problems. If the truck is having problems like yours I will run an LED from the starter into the cab. That way I know if the starter is getting a signal or not.

How old is the starter?

 

I just had a similar issue with a D5 dozer last week. Ended up being an intermittent break in a battery ground cable. If you're getting power to the starter itself when you try and crank and your ground back to the battery is good, likely the starter is on its way out. Sometimes if it has a dead spot you can smack it with a hammer or prybar and it might get you going in a pinch.

 

Had a similar issue. I would turn the key and hear a click-no-crank symptom. It would take a few tries before the truck would fire up. At first I thought I had bad electrical connections, and so I'd clean and inspect wires, but still this condition progressively got worse as time went by. After some simple diagnostics (with an extra battery and a simple homemade starter switch) the problem ended up being the starter. Once I got that bad boy off and opened it up, the problem was pretty clear - worn brushes. I just ended up replacing it with a remaned unit rather than using a kit. I haven't had any problems since then.