Blown46

I have a 1999 dodge ram 2500 4x4 quad cab and the passenger side window will not go up. It goes down just fine from both window switches but will not go up from either switch. I bought new southern doors, painted and hung them and everything worked fine. Then passenger side window wouldn't go up one day. ( Months after replacing the doors) At first I just figured it was the window regulator in my new used southern door, so I replaced the whole assembly and still no window going back up. Next I replaced the passenger side switch. Nothing. Then I read here on TDR that it could be the driver's side main window switch. Replaced that and STILL nothing. So I took the passenger side door panel off again and cut the wires from the regulator and reversed them and plugged it back in. Now the window will go up but not down. So I returned the wires to the correct way after the test. Checked voltage on both wires going to the window regulator/motor and have 12v power to BOTH. I'm ready to pull my hair out with this problem. Any help or suggestions on what to do next would be greatly appreciated.

texasprd

You might have 12V at your measurement point, but that doesn't mean the wiring is sufficiently intact to carry the current load for the motor. One strand of wire will carry 12V, but it won't carry enough current for the motor. Do a voltage-drop test (read up on this or ask how, if you need to) from switch to motor and from driver's switch to passenger's switch - and maybe from ??? to driver's switch (if only one power wire and only one ground goes to the driver's side switch, this isn't necessary - check wiring diagrams). If you find a large voltage drop, then you know you have a wiring problem that probably isn't easily visible, such as a pinched wire that is broken inside the insulation.

Humblecowboy

I replaced my DS regulator and later found that the connector would once in awhile lose contact and the window wouldn't go up. Luckily I hadn't replaced the panel yet so I just jiggled the connection and it went up. this has happened at least twice. I will put some dielectric grease in the connector before I replace my door panel. Try that and see if that fixes it. You might want to leave your door panel off for awhile to see if it works.

Blown46

How would I do the voltage drop test suggested above?

texasprd

You need a digital multimeter (DMM) and some way to back-probe the connectors at the switch(es), motor, and any other locations you are testing between. You can get leads with banana plugs at both ends so they go into "accupuncture probes" or other back-probe connectors, but for a cheap way to back-probe you can use sewing pins and the alligator clips that slip/screw on the ends of multimeter probes. Hold the pins with the clips and slip the pins into the backs of the connectors parallel to the wires so the pins make contact with the actual wiring terminals inside the plastic connector housing (don't puncture the wire) - do this on both ends of each separate wire that you want to test (i.e. up-power from switch to motor). Set DMM to DC voltage and load the circuit by pressing the switch for the desired direction. The reading on the meter is the voltage drop. Depending on how many connections (including splices/junctions) you are testing across on a given wire, I would say more than. 4V is probably excessive. If you are seeing 1.5V-2V, that is definitely excessive and indicates a problem. You need to do this for every wire involved - if it's a chassis/sheet metal ground, use the alligator clip and clean the ground.

I also suggest you do this across the switches, if you can determine the input and output connectors. I know you replaced switches but this may help you verify the condition of the switches or see if the wiring terminals are in good contact with the switch terminals.https://www.google.com/url?sa=t&sour...cRE6yzOaTegdmX
https://www.google.com/url?sa=t&sour...9658vFzjKQmcxp

https://www.google.com/url?sa=t&sour...fPOmnMxhdsiwtU

Above are some Google search results for "voltage drop test" - I'm not able to look at them right this moment to see how relevant they are, though they should be good. Note the ASE link for doing this on your starter circuit - I did voltage drop testing that revealed significant cable corrosion.

Remember, you want to put a "normal" load on the circuit while doing this.