This has been and off and on problem for quite a while. If I drive it every day, no problem. There are a pair of year old batteries, and the alternator is two years old. I did a standard draw test, and the test light lit dimly, and pulsed. The radio had a pulsing noise as did the CTM. I disconnected both and the noise went away, as did the draw. I hooked both back up, and the noise continued. I pulled the fifty amp battery fuse and the light went out, and the two components stopped making their noise.
Is there an online wiring diagram, somewhere that I can learn how this truck is wired ? Another thing, when I reconnect a battery cable, with both off, there is a pretty good spark.

Thanks

 

i have a wiring diagram for a 95 ford powerstroke ....is that what what you.re looking for?

 

I have the wiring diagram for a Honda Accord.
It doesn't help much if you don't tell us what kind and year your truck is.
You probably have to replace the CTM though, they fail quite often.

 

Don't troubleshoot it with a test light. I had the same issue that you were describing when I used my test light because my multimeter wasn't working. The light would pulse and I could hear the clicking under the dash. I pulled fuses and found the one that killed the clicking and figured my problem was on that circuit. I picked up new fuses for my multimeter and tested again and found that the clicking no longer happens and then I was able to find my draw.

I think the issue is that the test light wasn't carrying enough load to allow some relays to close, which caused the clicking as it tried repeatedly to close. When I watched the amp draw on the meter, the draw was high when first connected, then it fell off.

Here's the thread I had running while I was troubleshooting...

https://www.dieseltruckresource.com/...e-t263607.html