Originally Posted by Swoop
Okay, i have done some more research and wondering around with my multimeter. I opened up driver side lock switch panel and measured it and one of the pins has aprox. 12 volts coming as it should. Now on the passenger side, there is three pins and one of them has voltage at all times. 1v... Seems to me that it may not be quite enough.
I have Haynes repair manual and i try to look those lock wiring diagrams but colours aren`t the same on the manual and my truck. However if i understand correctly the power comes from the fusebox, goes to the passenger side switch, then continues instrument cluster and after that goes driver side door and rear doors. So if the "main brains" are in the cluster and it gets 1v it can`t operate any doors... At least i don`t think it could... In the other hand, this does`t explain why there is power in driver side mut no function.
While i was laying on the floor, middle of wires and pedals i looked up at cluster in case i might see something out of the ordinary. I noticed one empty slot in the cluster. Does it supposed to be empty or is there missing something, like keyless entry receiver? Heres a pic.
And thanks again!!
I know I'm going from zero to holy crap, but instead of nickle and diming this thing until we're all pulling our hair out by checking for continuity and power at all the switches and actuators, see if you can get an receiver from a junk yard, or see how much the dealer or a parts house wants for it. Switch them out, or if it's missing, plug this one in and see what happens.
A few questions for clarification:
1) Did you check for voltage at the driver's side switch or at the driver's side actuator? The switch sends a signal which triggers the instrument cluster. The IC then activates drivers that are internal on the IC that actuate the locks.
B) You said the driver's side is getting 12V - you said approx. 12V, is it more or less? Very important - and is it getting this 12V constantly or only when you try to lock/unlock the doors?
III) You said the passenger switch gets a constant 1V. Does that change when you try to lock/unlock the doors?
Here's an interesting tidbit I found out about our trucks. I love this 'cause I am learning too:
The door locks on a 2002-2008 ram truck are solely controlled by the instrument cluster. The instrument cluster has an integral body control module making it a cabin compartment node. The power distribution center (or Integrated Power Module) is under the hood along with the power control module. The only thing the PCM or PDC does (called the IPM on 02 and newer trucks) is this. When your vehicle speed reaches 15 mph the cluster looks at TPS position. It does this through the PCI bus system that the module communicate on. Vehicle speed is broadcast over the bus for all modules to pick up. If TPS is under 15% the CCN will lock the doors automatically. There is no power door lock relay. There is no speed sensor that makes a relay work. They are controlled by a low side driver from the CCN, not a relay.
This is very interesting because I always thought there was a relay. So, my next question is: Do the doors lock when you reach 15 mph?
I'm also wondering, since this is now a pretty simple system, if you A) have a bad cluster, 2) a broken, or partially broken, wire that allows 12V to pass but not enough amps and, lastly, my original thought of that being the receiver for the keyless entry is gone, lost power or on the fritz. Crap, there are two more possibilities, and they are the BCM and the CCN, and have either one of those decided to get stuck in stupid?
OY! Simple system, but complicated to troubleshoot.