I have a 2000 Dodge ram 2500 with the 24 valve 5.9 Cummins. My obd2 read out is showing all the codes that point to the ecm! My truck does start, far and few between, but my tack bounces and won't set on a certain rpm when idling, or it just falls flat while it's running. I went to take my ecm off today, and the wiring harness connector needs to come off. Well I read that you need either a 4 mil Allen or a 5/32 Allen to take it off, but it seems I have no place for those Allen wrenches to fit in there! I thought it was full of junk, but when I went to scrape it out, it's all metal! I don't know if someone broke the Allen wrench off in it before, but I'm stuck at the point I don't know what to do! Is there anyone that can help me out with this

 

It looks like the allen head of the bolt may be broken/rusted off. Have you tried to give the connector a good stiff pull to remove it, as it seems that the bolt is no longer holding the connector in-place?

 

I have not tried that yet! I will try it first thing. Thank you for you reply.

 

In looking at the photo closer, there may be just a slight bit of the bolt shoulder left to possibly cause the connector not to come off after that stiff pull (but try it anyway to see what you get). If the connector still won't come off, I'd suggest taking a Dremel tool with a grinding bit on it and gently grind around the sides of that rust bolt until the connector can be tugged off. Once the connector is off, you may be able to remove what's left of the bolt with some decent pliers. Wishing you all the best with your repair!

 

Center punch the center of what you have left, Then find a drill bit that matches the shaft size of the bolt. Drill it until it comes free.