CH123

I am out of town for a couple days, but here's what I can answer now- At the time the truck went down I showed codes 1689, 1693, and 0720. Not 100% certain all were new since I had some sensors replaced about a month prior, and can't recall if any codes present had been cleared (2 years ago now). Once I received the truck back to my possession a couple months ago the OBD was no longer communicating. I have not yet checked since reinstalling the ECM and PCM this week. I will check Friday. I had been on the road about an hour and half since my last refuel. Lift pump is working. At my last check it was around 13 PSI. I asked the last mechanic to inspect the battery connections. He did cut back some of the coating and confirmed there was not any corrosion inside. I'll reinspect all and the grounds once I'm back Friday.

I did not have any external power sources such as batteries connected. I am no longer focused on these wires. Ready to move on.

Very helpful. So to provide more accurate information to the original post, here are ohms readings to ground from the wires at what I believe to be J/C 8 as well as the positive battery lead. If not listed, the reading was OL. I noted baseline readings and which ones didn't change through the variable conditions. Baseline - door closed, ignition off. positive battery terminal - 154 Green w/ yellow - 48.6, no changes Black w/ pink - 0, no chnges Back w/ pink -0, no changes White w/ green - 8.1, no changes Door open, ignition off- Tan - 0 Yellow -0 Yellow - 6.1 White w/ green - 4.9 Positive battery terminal - 4.9 Door closed, ignition on- Positive battery terminal - 40.1 Green w/ yellow - 48.6 Yellow 54.8 Yellow - 58.1 Black w/pink - 0 Let me know if any of these are concerning. If not, we can move on to the main issue of throttle and power.

That connector is a capped joint connector combining each cluster of colored wires into a single circuit. I believe it to be J/C 8 in the '99 wiring diagrams, but the pin numbers do not match this 1998.5. I was under the impression I had an issue because I was getting the continuity tone sound on my battery cables even with the batteries in and engine running. This doesn't occur with my other vehicles in my driveway under the same conditions. I just thought I was using the correct setting for this, but I can certainly switch to ohms for any readings you would like me to provide. Thank you for the help!

So I shouldn't be worried about any of the wires circled in the first picture having "tone" to ground? What about when the engine is running? If I should move on, I still have this throttle / power issue to resolve. Any guidance on where to focus or what sensors and target readings I should be seeing?

Setting shown in picture below. I am tracking now with the batteries disconnected, however I also got the continuity tone with the batteries connected. I suspected the same regarding the dome light, but didn't understand why I have continuity with the ignition on, doors closed. I am proceeding cautiously to ensure nothing is missed that may re-damage my PCM and ECM.

Long time reader, first time poster. At my witts end. Bear with me while I bring you up to speed. I have a 1998.5 2500 automatic 2wd with roughly 155K miles. It was my grandfather's truck that I ended up with after his passing. It wasn't in good running condition, but after some TLC it was a dream. Work done includes - new turbo, ball joints, batteries, a/c, trailer wiring, tires, control arms, axle seals, belt, new suspension, cab lights, neutral safety switch, abs speed sensor, output speed sensor, and APPS. Two years ago it went down on me one night while driving down the interstate, and I'm still trying to fix it. I was on cruise and suddenly lost power, not died but lost 95% of it's output. The truck still cranks and runs fine but will only idle or jump to 1400-1500 rpm. There is no in-between or past. In gear it will barely roll in my flat driveway. The truck has been with 3 mechanics without success and now it's back to me. I found continuity between my positive and negative battery cables. I tracked to C1 of the PCM and verified I had continuity to ground from pins 4 and 22. I was also lacking ground continuity on C3 pin 28. I sent both the PCM and ECM to auto computer specialists and received them back this week. I reinstalled and all of those continuity issues have been resolved. After installing the ECM and PCM my multimeter was still hooked up to my positive and negative battery terminals. I opened the drivers door and heard the continuity tone. I have since determined I have short to ground when either door is open or if the ignition is in run or the back position. I have yet to understand the relation of the door jam switches and the ignition switch. Confirmed it goes through the IOD fuse. Attempting to track the short I came to this connector near the steering column. I have been using the 1999 wiring diagrams for a while, but I am not able to find this connector with correct pin numbers. The pins circled have continuity to ground, but I'm not clear on their path from here. Apologies for such a long post. Any guidance on where to go from here is appreciated.