Attention: TDR Forum Junkies 
Over the past 6 weeks I've been hunting down various electrical problems in my 2001. 5 2500 4x4. It started around Christmas time with the rear license plate lights flickering like strobe lights, then burning out... I replaced them with some LED lights intended for a trailer, and after a few days they started doing the same thing: the left license plate light started flickering off/on like a strobe light, then died completely; then the right light started doing the same thing. Not long after, when preparing to drive home from work one night, ALL lights except for headlights went out, taking the radio and heated/power mirrors with them.
I tracked the no-lights problem down to the IOD fuse in the in-cab fuse box, which momentarily fixed the mirrors, radio, and interior lights... but the next time I went to turn on the headlights, the IOD fuse blew again! I resolved to track this problem down once and for all.
I'd also been having problems with the transmission TC locking/unlocking around 45mph, driving me crazy. There were also some intermittent electrical issues throughout the truck I wanted to fix once and for all. Since I had more than 133K miles on the truck, I bought a brand-new alternator in case the diodes in the old one were worn and allowing stray AC signals to get into the chassis. The charge wire from the alternator was bundled with a number of other wires, including several ground wires, as it ran to the driver's side of the engine compartment to end in the power distribution box next to the driver's side battery... . I completely removed this wire, and replaced it with a 4-gauge heavy duty power cable, and ran this new charge wire along the top of the radiator, on top of the power cable that connects both battery positive terminals. Anywhere that the new charge wire could have potentially worn through or chafed against metal, I cut some fuel hose to fit over the charge wire, secured it with zip-ties, and then wrapped the entire length with plastic wire loom to protect it. I then used metal hose clamps around the fuel-hose-wrapped portions to secure the new charge wire to the positive battery cable along the top of the radiator, as plastic zip-ties don't last too long out here in the dry, hot desert climate.
I traced the ground wires running along the front of the engine back to their source, and found that they went to the APPS and a couple of other electronic appliances on the driver's side of the engine compartment... why these are grounded on the passenger's side of the engine compartment are beyond me. So, I cut these grounds, soldered them together, and attached them to a couple of large terminal connectors and grounded them directly to the driver's side battery (as others have suggested doing with the APPS ground wire). The other end of the cut grounds was secured to the body next to the passenger-side battery, so I soldered on another terminal connector and grounded this directly to the passenger-side battery negative terminal.
Going back to the driver's side of the engine compartment, the ground cable terminal was splitting, so I cut it off and replaced it with a Mil-Spec type from NAPA (it has 2 bolts going through it instead of the standard one). I cut back the ground cables to get rid of any corroded strands, and soldered on new terminal connectors. I saw that the large ground cable from the engine block was thoroughly corroded, so I replaced it with a newer, heavier-gauge one (with soldered terminals again).
Then, the fun part began: disconnecting every electrical connector I could reach in the engine compartment, checking each & every pin, cleaning thoroughly with electronics cleaner, and sealing with silicone spray. I paid extra attention to the PCM connectors on the passenger-side firewall. LOTS of corrosion and debris removed during this process.
But, it still didn't solve my short problem. So, I began taking the interior & dash apart to look for the problem. I found numerous areas where the stock wiring was rubbing/chafing against sharp metal edges, so I used a crapload of plastic wire loom to protect these from future problems. I disconnected the large connector on the driver's side firewall, cleaned everything after checking pin connectors, and still couldn't find the problem... WTH!
I had one of the Delrin steering shaft bushings another TDR member manufactures and sells, so I took this opportunity to remove the steering column and install it... while I was reinstalling the column, I again checked & cleaned every pin and connector on the column. Still, no cause for my electrical short could be found; I was ready to start pulling out what little hair I had left. #@$%! :{
I thought maybe the problem might lie in my gauge pod mounted to my driver's side A-pillar, so I took it down and started to fix every connection & wire I could reach (soldered & heat-shrunk). I wanted to reach some wire connections behind the headlight switch (replace the scotch-locks there that were powering the gauges in the pod), so I removed the headlight switch.
BINGO! After I removed the headlight switch, I heard something rattling around in it, and as I started to gently shake it, copper parts & springs started falling out of it... . HMMMMMM..... I bought a new one and installed it, and wouldn't you know, my IOD fuse stopped popping and I had full electrical power back! Oo. Oo. Oo.
I also replaced the speed sensor that mounted in the transmission, fixed a few other non-electrical non-related problems, and now the truck runs, drives, and shifts like it was almost new! WHEW! I got my license plate lights back with no flickering, and no other problems. I even placed a code reader on the ODB port to verify that no codes were being thrown, in case I missed something... but no codes! Everything is running fine.
Several times I completely cleared the ECM/PCM capacitors by disconnecting the negative battery cables, turning the ignition on & leaving it on for several hours, then disconnecting the positive battery cables and leaving the ignition on for several more hours. Once reconnected, I calibrated the APPS (just in case) by slowly depressing the accelerator pedal and slowly letting it back up. The APPS works like new, I haven't had any of the previous problems since and all that hard work was well worth it.
Of course now that I've been driving it around, the power steering pump is starting to really puke fluid... I guess now I need to rebuild it and the vacuum pump while I'm at it. There's also power steering fluid leaking from the booster behind the brake master cylinder, so hopefully I can fix all these easily and be good for another 10-15 years.
I apologize for this being so long, but there were so many stupid little problems I hope that this might help other 2nd-Gen owners having similar problems. Start with replacing the headlight switch if you start having issues like I did with rear lighting!
I tracked the no-lights problem down to the IOD fuse in the in-cab fuse box, which momentarily fixed the mirrors, radio, and interior lights... but the next time I went to turn on the headlights, the IOD fuse blew again! I resolved to track this problem down once and for all.
I'd also been having problems with the transmission TC locking/unlocking around 45mph, driving me crazy. There were also some intermittent electrical issues throughout the truck I wanted to fix once and for all. Since I had more than 133K miles on the truck, I bought a brand-new alternator in case the diodes in the old one were worn and allowing stray AC signals to get into the chassis. The charge wire from the alternator was bundled with a number of other wires, including several ground wires, as it ran to the driver's side of the engine compartment to end in the power distribution box next to the driver's side battery... . I completely removed this wire, and replaced it with a 4-gauge heavy duty power cable, and ran this new charge wire along the top of the radiator, on top of the power cable that connects both battery positive terminals. Anywhere that the new charge wire could have potentially worn through or chafed against metal, I cut some fuel hose to fit over the charge wire, secured it with zip-ties, and then wrapped the entire length with plastic wire loom to protect it. I then used metal hose clamps around the fuel-hose-wrapped portions to secure the new charge wire to the positive battery cable along the top of the radiator, as plastic zip-ties don't last too long out here in the dry, hot desert climate.
I traced the ground wires running along the front of the engine back to their source, and found that they went to the APPS and a couple of other electronic appliances on the driver's side of the engine compartment... why these are grounded on the passenger's side of the engine compartment are beyond me. So, I cut these grounds, soldered them together, and attached them to a couple of large terminal connectors and grounded them directly to the driver's side battery (as others have suggested doing with the APPS ground wire). The other end of the cut grounds was secured to the body next to the passenger-side battery, so I soldered on another terminal connector and grounded this directly to the passenger-side battery negative terminal.
Going back to the driver's side of the engine compartment, the ground cable terminal was splitting, so I cut it off and replaced it with a Mil-Spec type from NAPA (it has 2 bolts going through it instead of the standard one). I cut back the ground cables to get rid of any corroded strands, and soldered on new terminal connectors. I saw that the large ground cable from the engine block was thoroughly corroded, so I replaced it with a newer, heavier-gauge one (with soldered terminals again).
Then, the fun part began: disconnecting every electrical connector I could reach in the engine compartment, checking each & every pin, cleaning thoroughly with electronics cleaner, and sealing with silicone spray. I paid extra attention to the PCM connectors on the passenger-side firewall. LOTS of corrosion and debris removed during this process.
But, it still didn't solve my short problem. So, I began taking the interior & dash apart to look for the problem. I found numerous areas where the stock wiring was rubbing/chafing against sharp metal edges, so I used a crapload of plastic wire loom to protect these from future problems. I disconnected the large connector on the driver's side firewall, cleaned everything after checking pin connectors, and still couldn't find the problem... WTH!
I had one of the Delrin steering shaft bushings another TDR member manufactures and sells, so I took this opportunity to remove the steering column and install it... while I was reinstalling the column, I again checked & cleaned every pin and connector on the column. Still, no cause for my electrical short could be found; I was ready to start pulling out what little hair I had left. #@$%! :{
I thought maybe the problem might lie in my gauge pod mounted to my driver's side A-pillar, so I took it down and started to fix every connection & wire I could reach (soldered & heat-shrunk). I wanted to reach some wire connections behind the headlight switch (replace the scotch-locks there that were powering the gauges in the pod), so I removed the headlight switch.
BINGO! After I removed the headlight switch, I heard something rattling around in it, and as I started to gently shake it, copper parts & springs started falling out of it... . HMMMMMM..... I bought a new one and installed it, and wouldn't you know, my IOD fuse stopped popping and I had full electrical power back! Oo. Oo. Oo.
I also replaced the speed sensor that mounted in the transmission, fixed a few other non-electrical non-related problems, and now the truck runs, drives, and shifts like it was almost new! WHEW! I got my license plate lights back with no flickering, and no other problems. I even placed a code reader on the ODB port to verify that no codes were being thrown, in case I missed something... but no codes! Everything is running fine.
Several times I completely cleared the ECM/PCM capacitors by disconnecting the negative battery cables, turning the ignition on & leaving it on for several hours, then disconnecting the positive battery cables and leaving the ignition on for several more hours. Once reconnected, I calibrated the APPS (just in case) by slowly depressing the accelerator pedal and slowly letting it back up. The APPS works like new, I haven't had any of the previous problems since and all that hard work was well worth it.
Of course now that I've been driving it around, the power steering pump is starting to really puke fluid... I guess now I need to rebuild it and the vacuum pump while I'm at it. There's also power steering fluid leaking from the booster behind the brake master cylinder, so hopefully I can fix all these easily and be good for another 10-15 years.
I apologize for this being so long, but there were so many stupid little problems I hope that this might help other 2nd-Gen owners having similar problems. Start with replacing the headlight switch if you start having issues like I did with rear lighting!
