Before I go through my current problem I will give a brief history relating to this. Roughly 2 years ago I had the on board computer (believe this is what it is called) replaced because of windshield leaking in top corner of drivers side which ruined this unit. since then the vehicle has not had any similar problems and I believed the leak was permanently fixed. About 1 week ago on 2-12-11 I went to try and start the truck and noticed battery was dead so I charged and load tested to find out it was no go. battery was replaced by employees and starter kept cranking. replaced the relay and starter and turned on and off roughly 10 times using an older battery. Everything seemed fine. had my employee install new battery and trucks starter kept cranking and the flat ground cable from the firewall and connected to back of engine smoked and actually caught fire.
I am not sure what the problem could be. The truck has been sitting for approx. 2 months without moving and has been covered by snow, so I suppose it is possible that some water could have leaked in, however even if it did my mechanic had covered the computer with a plastic bag and sealed up properly. He's older mechanic with years of exp. and really leaves no stone unturned so he fixed it properly.
I had the starter tested and saw the starter gear come out and turn the way it should and relay is new.
I am going to call to have truck towed to my mechanic, unless someone can help out so that at least i could drive the truck to him.
Easy to diagnois... Key turns voltage goes to solenoid on right fender behind battery..That solenoid energizes and low current power goes down to starter on small wire to energize solenoid on starter...
Problem could be ignition switch, solenoid on fender, solenoid on starter..
Take big wire off starter.. does solenoid on fender click on? if so take small wire off that solenoid. Does it still click on? I wouldn't think so. That small wire comes from the key sw. So key sw on, solenoid on fender on, voltage down to solenoid on starter engages high amperage contact to turn starter. This should enable you to quickly find problem. Nothing else is connected in this mess except if you have a remote starter..
Thanks for the reply. I understand what you have told me however I would think that for the starter to continue running, it needs to get power through the fender mounted solenoid so the solenoid would have to be stuck in the closed position for starter to crank? How would I bench test the starter to make sure the the motor and solenoid are working properly? How did the ground cable catch on fire?
Cables will get hot if cranking too long...No the upper solenoid does not have to be bad to enable the starter to go run by itself. The lower solenoid on the starter may be bad.
Hook up the starter to the big wire not the small. If it runs the starter is bad. The small terminal jumped to the big wire should engage the starter.
Its much easier to work in the area of the upper solenoid. Disconnect the wire going down to the starter. does the starter still run by itself? If so its the starter.
Don't forget the solenoid on the fender doesn't supply power to the starter like the older trucks. It just supplies a small wire to trigger the solenoid on the starter. The big wire goes from the battery to the solenoid on the starter.