Lost all power to the Passenger Door Module (PDM) the other day (have new unit on order). However during the troubleshooting process I discovered a problem with the PDM wiring. So I checked the 10A PDM fuse (left side of dash) and the 25A fuse at the IP Block near the drivers footwell - both OK. So then checked for voltage at the IP Block on right side of dash, both of which should be hot at all times per schematic. The 25A line voltage was ok. But the PDM voltage was zero. Suspecting a broken wire, I tried a continuity check with my VOM from the RH IP Block pin to the pin at the PDM fuse slot and there is good continuity! Put the fuse in and ZERO volts. Not sure I understand that, so hoping someone here may have come across this before. TIA folks.

 

check the continuity from the 25A Circuit Breaker back to the PDM connector, it could be a broken wire in the door harness.

 

Not sure how ground is ran in the door if its just through the frame or it has a wire. make sure your testing voltage from a known good grounding source.

 

Yes sir, all wiring from plugs (orange wires from plug in following picture) to PDM in door module checked good including grounding wires to a chasis ground point. The 12V from the 25A fuse is present at the IP Block in first set of pics. But the 10A fuse voltage going to the same IP port is 0V even though the wire has continuity. Can't get to the PDM if it isn't at the port pin 7C shown on schematic. While this would normally mean an open/broken wire, the wire seems good via the VOM continuity check.

 

That voltage is good all the way to the PDM. SUSPECT 2 ISSUES - PDM internal issue such as cold solder joint or blown components as nothing works - FOB, window, lock & mirror control are all out. Since the 25A 12V was good to the module at least one of those ckts should have worked. 2nd issue is lack of the 12V at the Right dash IP Block which should be hot at all times from that fuse. That feeds the B+ for the module (FOB & Data ckts). I have a new module and some orange wire on order which I can use to rune a new line. I'm just stumped on how I can have continuity on a wire and yet it won't pass voltage/current.

 

Don't be stumped, scientifically a low ohmic (i.e. good) wire connection simply cannot have voltage at one end and not the other.

The tiniest details can be key when looking for faults:

1. by 10A fuse do you mean the PDM 15A? (shown as 15A on your diagram) I mention this in case you're looking at the wrong fuse? (it should be 15A right?)
2. the RT Door 25A is a "resettable breaker" not a "fuse" per say. For completeness, the PDM uses this line to solely power the window motors (via C1 Pin 2) The PDM electronics is powered via C2 Pin 14 i.e. via the PDM fuse. The module may still function without the 25A windows voltage, but may set a DTC (not 100% sure) however I believe the PDM will still be operative, obviously the windows will not work.
3. the PDM absolutely will not work without voltage on C2 Pin 14.
4. when checking continuity be sure the multimeter is set to the "low" ohms range (usually 0 to 200R scale) On higher ranges, or auto-ranging, you may get misleading readings from various alternate feedback paths. Low resistance is vital e.g. less than 1 ohms, ideally zero. Also disconnect the main battery when measuring.
5. an intermittent wire may read "low" sometimes but fail under load or when flexed, i.e. with door movement.

If there's low ohms from PDM connector C2 Pin-14 to I/P Junction Block connector C7 Pin-C then your door wiring is likely OK.

If I/P Junction Block C7 Pin-C connects to C1 Pin-7C this module should be OK

In this case, either the 15A PDM Fuse is open circuit, or the connection from I/P Junction Block C1 Pin-7C to I/P Relay Block C1-A7 is broken or there is a fault with the I/P Relay Block module.

Sound like your missing +12V on C1 Pin-7C suggesting the PDM fuse or and issue with the Relay Block

Hope you find it....

 

OceanBrave -- Thanks! Re:
1 - Yes, I indicate 10A fuse because the owners manual and label on the fuse panel legend all indicate the PDM fuse should be 10A, and that is what has been in the panel ever since I have owned it. Suspect the schematic may be in error.
2. Agree with all. The 25A/12V voltage is present at the PDM module, but PDM switch for window does not operate, presumably due to lack of the PDM voltage to power the rest of the internal electronics and returning data signals to the BCM. And absolutely no codes being thrown.
3. Yep.
4. I may have had it on the 2nd lowest setting, but will be rechecked today and will pay close attention to that. Going to see if I lose the continuity while pushing/pulling on the IP Block pins or wiring behind them I can reach.
5. That is all I can guess at this point. Door harness checked out good when we tested it. Took a while but every wire checked ok to respective plugs inside at the block with door movement. I suspect there may be a break in the wire which has a small enough gap that it passes the very low conductance test V/C from the VOM but cannot pass higher voltage/current. Or perhaps a bad crimp on the Fuse/IP Block pins. Thus wire is on order to ensure I get 12V to the new PDM module arriving next week.

I appreciate your time and thoughtful responses.

 

PGI Conch apologies, you are indeed correct the PDM fuse is 10A, I have amended my pdf accordingly.

“But the 10A fuse voltage going to the same IP port is 0V even though the wire has continuity “

Simply can’t be, if there is no voltage on 7C there has to be a break in the circuit from the PDM Fuse to I/P Junction Block C7 Pin C. You can confirm this by measuring between the little pins on the fuse itself and 7C, short the probes of your VOM and check they read very similar i.e. very low ohms ie < 2)

The I/P Fuse block has a PCB inside with a large multi-way connector on the back, the I/P relay block is similar but with 2 large multi-way connectors, have to say both blocks look very intimidating to work with, however I suspect somewhere between them lies the problem.

“Or perhaps a bad crimp on the Fuse/IP Block pins. “

could well be or a bad PCB connection inside one of the I/P blocks, or in the main internal harness.

 

So put 12V on the right dash side IP Block pin. Tested at left dash Fuse block pin and got the 12V telling me the wiring was good. Re-assembeled the Pass Door PDM and connected all wiring. Without the PDM fuse in I supplied a 12V line to the PDM connector and everything worked again! Voila. So, realized problem must be at the interior fuse panel block. Figuring good fuses didn't work, took a short piece of wire and put it between the fuse pins (no fuse). And again everything worked! Plug the fuse in and crapola. WTH! So put a small radial bend in the fuse pins and it is working for now. At least I know the issue is in the fuse block pins. Not sure replacements are available or what the change-up would entail. At least I can return the PDM and start the hunt for a new fuse block. Hopefully they aren't too terrible to replace.

 

PGI Conch well that’s a result!!!! - good job and thanks for the update.

Before you all say yeah, yeah, sure, of course you did, I’ll just say this.

I’m struggling posting on the forum, frustratingly and randomly after writing a reply, the page will freeze and I get the message “Page Unresponsive” you can’t copy, save, post or refresh, all that you can do is scroll up and down, or take a screenshot. It could be the browser I’m using (Brave) or an addon (adblocker) or something, but it happens all the time, so I’ve taken to editing a word doc and copy and pasting from there – it’s safer.




Anyway, after 3 attempts today, where I pretty much suggested everything you did, even down to the dodgy fuse connection, I gave up and just wrote a precis (much to everyone’s relief no doubt)

What I also mentioned was that used I/P blocks of both types are available on eBay, also perhaps a bit of contact cleaner would help, as hummerz would normally suggest.

Again, good job.