Dodge Repair/'01 ram 2500: electrical circuits "out"
Hey there. My 2001 dodge ram 2500 diesel has no power to the door locks, power windows,or the blower fan. I have replaced the ignition switch but not the key tumbler. The truck will start and run but shifts funny and speedometer will not work. The abs and air bag lights remain on constantly. I can't find a good diagram of the harness at the ignition switch to verify where power should be. I do know that I have continuity from the switch end to the cluster plug under the dash on the firewall. I have checked all the fuses and relays check out as near as I can tell. I'm at a loss for where to look next. Also wipers and headlights function normally. No remote start installed. Radio was replaced last week and no problems until now. Any information or suggestions would be greatly appreciated. Thanks in advance.
I don't see a single cause for every problem that you have listed. Did they all begin at once?
It wasn't clear to me if the radio now works or not, so let me know about that.
There are basically three different sections to the ignition switch and I find that problem areas are powered by two of the three sections, but I don't find that everything on either of those two sections are not working so at least for now I would not blame it on the ignition switch. I can mention things that are also powered by each of those section so you can verify that they are or are not working as a check.
The power door locks depend upon fuse 13 of the junction block box in the cabin, and that fuse is powered directly from the battery, so no involvement of the ignition switch.
The power windows are based on a circuit breaker #1 in the junction block that gets its power from a section "22" of the ignition switch.
The blower motor is powered directly from the battery, through fuse 12 in the power distribution center(PDC) in the engine compartment with no involvement of the ignition switch. It may be the blower motor resistor block itself has 'opened up' which is the more common cause for that.
Air bag is powered by fuses 18 and 19 in the junction block, but 18 is on section 22 of the ignition switch, while 19 is on section "21" of the switch. Similarly the ABS needs fuse 3 of the junction block and section 22 of the ignition switch as well as fuse 11 in the power distribution center which is direct from the battery.
The speedometer is operated by the digital data bus (but also there are other cluster readings that run on that same bus, so I wonder whether the digital data from the transmission speedo sensor might be not getting through the bus to body control module. The abs and the air bag also need that data bus to work, so that might explain why their warning lights are "on".
That is what I found so far, so let me know about my questions and also about what you now can check out.
Thanks for the rating and nomination.
PS: section 22 also powers the back up lamps and the radio, so if both those are out, then indeed 22 of the ignition switch may be bad, but see whether the fuses it power when the key is in the run position are showing 12v or not. They are 2,3,7,18, and circuit breaker 1, all in the junction block