When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Alright so I checked continuity from the 42 pin connector to the CPS connector and it tested good. I then checked continuity from the 42 pin connector to the PCM, and it did not have continuity. Just to be sure I was doing it correctly, I used pin 39 on the 42 pin connector and pin number 21 on the PCM connector.
Assuming I did the continuity test correctly (my probe was too large to fit in the tiny hole of the PCM connector so I put a paper clip in it and touched the probe to the paper clip and held it) what are my options at this point, or rather what is the best option? Should I follow the wire from the 42 pin connector to the PCM connector and trying to find where the wire is broken/frayed and repair? Or purchasing a whole new wiring/harness from the PCM to 42 pin connector? What do you guys recommend?
Also, if there is something I'm missing or doing wrong please advise. Thanks!
Years ago I bought a spare engine wiring harness as a hedge against problems such as this. NOTHING lasts forever and I had to deal with some crappy wiring harnesses when I was still working on cars. Mostly at the connectors, they would get corroded and/or expanded out so they would be a poor connection in the plug. Now retired, thank God.
It seems genuine Motorcraft part bags will have a little punch hole in them. I do not see any punch holes in your photo. I have not looked at a CPS part bag however so someone with experience will need to chime in.
Genuine parts can be purchased at dealer, Riffraff, or some of the other FTE site sponsors. My go-to for this type of stuff is usually Riffraff. People seem to trust Rock Auto as well.
It does sound like you’re getting to the bottom of this in the wiring. I would wait for someone to confirm the pin locations (keeping in mind which direction a diagram may show) then probably keep digging on it a little more to see if you can find the bad spot, or at least get a good confirmation before dropping a bunch of cash.
Be careful sticking things into the holes of connectors. This could expand the pin and cause further connection issues. Oh I’ve probed stuff like this too so not criticizing, just sharing a warning. I think the preferred method is back probing (from the back side of the connector) but depending on the connector type I don’t like breaking a seal if it’s present.
I was hoping someone would confirm my pin locations but nonetheless I was pretty confident in the diagrams I was looking at so I decided to disconnect all the connectors around the PCM so I would have access to the wires leading to the PCM harness. I’m not sure if this is normal but please see the picture I attached.
there is a yellow wire joined to the CPS wire on the back of the PCM connector , the wire goes from the CPS wire into a hole in the firewall and I’m guessing ends up somewhere under the dash. The green CPS wire looks all but broken right next to the connector. Was the yellow wire there from the factory or did a previous owner do this? Any guidance would be greatly appreciated.
You found it, yes? That's definitely not stock - pull that bad boy spilce off of there and repair that connection and see what happens. Nice work. Sometimes all it takes is getting your eyes along the harnesses.
Looking at another '02 '03 schematic, it shows the same pins for CPS signal - I think you got it.
Yes I did! Not sure if you could tell in the picture but the wire was hanging on that 3M splice connector by just 1 strand of copper. Still not sure what the spliced wire was for, crawled under the dash and followed the wire to a butt connector, not sure what they were trying to accomplish. Im close to soldering it but have a couple other things to take care of this evening but I will report back when it’s done 👍, and hopefully I’ll be reporting it fired right up!
Edit: the pins were definitely correct as I actually pulled the red retainer out of the PCM connector, and pulled the pin out to make the repair a lot easier
My guess is previous owner's attempt at a theft deterrent. There is probably a hidden switch inside under the dash?
That makes sense to me - that wire probably went to a switch in the cab at some point, to ground the CPS signal and prevent an unauthorized start.
Originally Posted by callforfire
I absolutely despise those wire splicey things. Gotta be the worst possible way to go about it.
You are so right. I'm regretting using some T-splices on some illumination circuits for my auxillary switches in the cab. Thought they'd be protected and work ok, but already they are becoming intermittent in the cold weather.
My guess is previous owner's attempt at a theft deterrent. There is probably a hidden switch inside under the dash?
I agree with this thought. And this scenerio is the reason I haven’t added a CPS kill switch to mine. I don’t like the thought of making splices on sealed factory wires.
To the OP, great job locating the issue. We look forward to hearing you tell us how good it runs after the repair!
I agree with this thought. And this scenerio is the reason I haven’t added a CPS kill switch to mine. I don’t like the thought of making splices on sealed factory wires.
To the OP, great job locating the issue. We look forward to hearing you tell us how good it runs after the repair!
I wonder if the previous owner fried the PCM by grounding out a circuit that wasn't intended to be in the first place. That would explain the lack of a switch installed now.
I’ve used the heat shrink butt connectors before and didn’t have a problem, however I opted to solder them and put liquid electrical tape on it this repair.
I just finished reassembling everything and she fired right up!!!! Wow! I’m very grateful for all
the help from the members of this forum.
Now I just need to figure out why the 4x4 won’t engage but I’ll start another thread for that!! Thanks again guys
Great news - that's a fine rig there. I wonder if you had to get to 10+ posts before you could upload a pic? I dunno.
Hoping we can help you with the 4x4 issue. I had a few issues with mine that ended up being a loose connector on the transfer case motor, and a broken wire between the GEM and the 4x4 relays under the hood. It will be interesting to see what symptoms you have.
Rezvani's Latest Post-Apocalytic Monster Is a Ford F-150 Raptor Underneath
Slideshow: Called the Fortress, the 850-horsepower pickup combines Raptor underpinnings with military-inspired features, survival equipment, and a starting price of $285,000.
