Sporadic Starting Problems

Cheap insurance: replace the negative cable from the starter to the frame. This is a "known" problem on Freightliners that can cause a host of electrical problems, including burning out the solenoid on that newly replaced starter.

 

Good advice! Just a little electrical resistance from the battery to ground can cause a host of problems!!

 

The magnetic switch on the dash sounds like the culprit, if it does not work and you have a test light, there are two small wires and two larger ones. One large wire will have constant power, the small wires are one from the ignition switch, it should power up when you push the button, the other small wire is ground, if you have power at that wire it could be a bad wire or a loose mounting grounding screw. If you have power to one small terminal, when the button is pushed and no power at the ground terminal, and good power at one bigger terminal and not the other then the Mag switch is bad if you have power to both larger terminals then check the starter the solinoid has two large and two small terminals. If you have power to both small terminals then the solinoid ground is bad. If you have power to one small terminal and a good ground on the other and power to both large terminals then the solinoid is OK. If you have power to the post on the starter, and a good ground then the starter is bad. All of this is done after you have cleaned and protected all battery and ground connections. Cleaning connections you can do for free, testing you can do, mag switch you can do. A bad ground will give you lots of problems, as has been stated. A test light and a volt OHM meter will save you a fortune.

 

I have a very similar problem with my KW C15. I just replaced all three batterys, had a 1500W heater installed, and if I leave the truck sit for more than 48hrs, she wont fire! I have had truck to my mech, he checked frame ground, battery grounds and yet she still dies if not run everyday! Anyone have any suggestions? Is there anything that would be pulling current while shes sitting in the garage. Truck runs great once shes running, ampmeter showing 14V once fired.

 

When you say APU, r you referring to the block heater? I would agree, but the truck sits in a garage that maintains approx 40 degrees. All my other equipment starts fine! My batteries read 11.3V when they wont crank her over. Dont think its a starter cause it never hesitates when Im running her. Seems like something is drawing a small amount of current.

 

sounds like something is drawing current while truck is off.

 

It could be as simple as the batteries are dirty on top and draining that way. Take a volt meter and put one lead on the positive and the other go around the top and see what kind of voltage you get.

 

Truck is a KW T-800 dump not a tractor, not to many frills, all three batteries have been changed 2 months ago. No refrigerator, no CB radio. the only thing that possibly could be on is the radio clock! The voltage holds 12.3V if I run her everyday. If she sits for more than 48hrs is when the batteries die. I have been reading others havin similar probs, im wondering if the starter relay is sticking causing a current draw.