I recently bought a ford f250 1992 7.5l and it started showing issues day one. I ran the codes and visted several forums from google searches. I pulled the harness plug and checked for exposed wiring and it seems to be in decent condition. My codes are 91,92,93,94 Engine off. These all translate to some solenoid circuit failure. My guess would be replace the pack, but before I go crazy replacing parts at random I thought I would see what others think. I find it very odd for all solenoids to be failing at one time.

 

Start by checking power at the connector. Pin 1 red and pin 12 white with red. Then, Ohm out the solenoids, pin 1 to 2, 3, 4 and 5.

 

Are the contacts clean?

 

The contacts of what? The solenoid? Pack male end, female end, or something else?

 

You'll have to excuse my ignorance when it comes to electrical knowledge. What I read from that was grab the solenoid female end of wire harness and use a ohm meter to detect resistance. Now when you say pin do you mean to stick the test prob to put red prob in 1 and black probe in 12. Then 1,2,3 etc and see if it reads 0 ohms?

 

The contacts of the connector. The wires are known to be damaged by heat from the exhaust pack.

 

NEVER put a probe in the end of the connector that makes the connection. That can spread the pins open so that they no longer will make contact with the mating connector. ALWAYS probe the back side of the connector.

 

The best way is to unplug the PCM Computer plug and plug the PCM harness connector into a Brake-Out-Box (BOB) and use your meter at the BOB.

BOB are nice for all kinds of tests on your OBD-1 trucks. You don't have to crawl under the truck to get to plugs and you do not have to stick pins in the wires. I have four OBD-1 trucks and it sure comes in handy for my trucks.

 

pin 1 and 12 should have 12v with the key on at the harness connector. Red lead on the meter to pin 1 and back lead to ground, then red lead to pin one black lead to ground. as Mark said dont jam the test lead into the pin, better to back probe it. If that checks out, then should measure the resistance of the solenoids at the pack itself or at the pcm. Best to get a wire diagram so you can get a better understanding of how it's laid out.

 

Image is for a 1995 and newer.
Wrong wire colors for wire 361 and its layout 1992-1994.
The pin out is right but pin 12 has the wrong wire color.



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I appreciate the help so far. I bought a multimeter this morning and have gone through all the fuses in both the cab and engine bay. I'll crawl under and check through the plug through the back vs the front.

 

Alright I just tried to run continuity as well as a ohm test and didn't get any feed back on the connector. So maybe there is a possibility that I am doing it incorrectly. I set my multimeter for the continuity setting (symbol with triangle going through a cross) and OL was only read. Also I tried tge ohm200 and ohm2000. Made should I was pinning red and working my way through 2 through 5 with my positive in 1 and negative touching the others. Am I supposed to have my key on engine off when I run these tests? Am I just doing them incorrectly? Also I want to mention there were a few fuses bridged with tin foil in the engine bay fuse box and the fuses were burnt out. I replaced them with new ones, but I assume they will just blow again.

 

Thank you.

 

Alright I bought some little pin probe tips for testing the connector. I also did some research on how to check for power 20v dc because we expect 12v from a healthy key on engine off connection. I also ebayed the 1992 shop manual and the 1992 electrical and vacuum manual for this F250. It seems to be hard to find complete drawings online so I assume buying those was my best bet. I checked both pins 1 and 12 at 20v dc on my multimeter with the red probe in and black probe grounded to the frame. Pin 1 (Red Wire) gave back a reading of 0 so I assume I have a power wire problem. Pin 12 (White, Red Stripe) came back at 12v. So that means either A my connector is bad in one pin or B there is a problem with the red wire up the line. What is the next step I should take? I traced the cable as I mentioned earlier, but it just webs off into several directions. Thank you.

 

I have no idea what slot 1 and 2 are or where you found the white wire with red stripe.
Are you saying pins 1 and 2?