Preface - 94 CTD, 2wd

I just did one of those dumb, brain fade accidents that will cost me a lot of down time and or money. I was trying to fasten the rubber weather stripping at the back of the engine compartment that seals the rear most part of the hood just behind the windshield wipers. I drilled a few holes and stuck a nail just to hold it in. While I was drill the hole, I was holding the strip up and hiding the wires behind it and of coarse I drilled through big bunch of wires. That wasn't so bad but when I put the nail in, it touch most of the wires where the drill scraped away the sheath and basically shorted them all out. Great.

Here's the after effect. I have no tach, speedo, air conditioning, overdrive nor torque converter lockup. The truck runs just fine as long as I don't go on the freeway.

Upon inspection, there are no blown fuses and none of the wires where completely severed. What I need is to find a wiring schematic and what systems I screwed up. I need to find out the computer, relay, fuse, whatever it is that was shorted so I can try to fix it. I also want to avoid taking it in because electrical work is expensive.

Thanks

Greg

 

The best thing for you to do is to buy a factory repair manual. They have all the info you requested in them. As for the repairs, you probably have wires shorted together even now. The arc may have broken the current path in the circuits in question. Try making the appropriate splices and insulate the wires. That may solve alot of your problems.

 

It sounds like you got the vacuum line as well, no cruise, ac are give aways

 

It's not the cruise it's the overdrive doesn't work. Actually, the button doesn't even light up when I press it.

 

I just tried to put electrical tape around the wires were nicked and nada. I disconnected batteries hoping it might reset any computers that might have been compromised and will reconnect them in the morning. keep your fingers crossed.

 

You need a wire scematic in the worst way. Where are you in relation to San Diego? You can go online to SOCAL Rattlin Rams web site here;

http://www.socalrattlinrams.org/

and see if someone is close enough to let you look at a diagram. Then it's just the time to do wire repairs and replace fuses. There are a lot of people in the LA, San Diego area that would probably lend a hand.

 

You won't find a schematic for the inards of the pcm anywhere, but here's the wiring.
https://www.dieseltruckresource.com/...sort/1/cat/500
click on picture to enlarge

There are some self resetting breakers in the PCM that may be still tripping from a slight short. The problems you exhibit point me to the engine speed sensor, the nail could have shorted and fried it. The pcm is very tough though, doubt if that's the problem.

 

I think it is the PCM. I unplugged it and the same results. I have one on order so I will let you know what the results are.

Thanks for all the advice.

Greg

 

I've worked a lot on the electrical systems on these trucks and have never seen a pcm fail except in the part that regulates battery charge only. Hope the new pcm fixes yours but don't hold your breath, the dealers love to throw a new pcm at them with no results. I know a few guys who have extra perfectly good pcms because of this. The pcm has internal breakers, it protects itself.
You didn't mention if you unplugged the pcm to fix the damaged wires. I've run across several that didn't make good connection when the pcm has been disconnected a few times, the female connectors seem to stretch out. This problem totally mimics a bad pcm. Fix is to take the plug apart and squeeze the connectors back together tighter.

 

Gregway, did you get the problem resolved. What was the fix?