2006 EB Rear HVAC Inoperable / Fuse, Relay, Resistor Good

[2006Overlander]

Again and again boss I appreciate your continued help with this. I’m gonna try and run to the local pick a part here in town and knab a resistor while I grab a few other parts. I’ll try that and report back, if not, I’ll just grab a new one and do the same.

 

[2006Overlander]

Update:

Wreckyard resistor did not help.

 

[whtbronco]

Well dang, I was hoping the used resistor would resolve it. They don't fail that often so it was certainly worth a shot.

Glad to help, just wish I had an answer or better idea for testing it.

 

[2006Overlander]

Now I’m at a complete loss. Like actually irritated beyond belief. The only things I have left to think about I the entire EATC unit in the front. But then how would the rear still receive power?

Also the 2nd row switch panel. Then again, how does it receive power?

At this point I think we have narrowed it down to a complete signal issue. It has to be a signal issue. Because if I’m still able to show power at that plug in the rear, it’s just not telling it to use the power

Or at this rate I’m gonna hook a switch up to it and just run it on high through a switch

 

[whtbronco]

I'm kinda going back to the beginning here. In the first post you noted you had power at pins 30 and 86. Pin 30 should be battery power, pin 86 should be switched power from the fan control switch and pin 87 should be power out of the relay to the fan. So in essence pin 86 is signal. You didn't mention pin 87. Did you get power on pin 87 when you had power on 86? Did you verify the ground on pin 85?

This is why I mentioned that electrical issues can be maddening. To figure out.

Another thing to consider would be performing a voltage drop test on each circuit. It's not hard, but can take some time.

How to use a Multimeter, Part 5: Measuring voltage drop - Hagerty Media

During the past month, we’ve covered how to use a multimeter to measure the trinity of voltage, resistance, and current. I’ve explained how this covers most electrical diagnosis in a car—how most of the time, you’re either trying to verify the presence or absence of voltage to a device or the...

www.hagerty.com

 

[whtbronco]

Here's the pinpoint test for the auxiliary fan inoperable. Not sure it has anything you haven't done, but it won't hurt.

 

[whtbronco]

 

[whtbronco]

This is also interesting:

BLOWER MOTOR RESISTOR

The blower motor resistor:
is located on the plenum chamber near the blower motor.
has three resistor elements mounted on the resistor board to provide four blower motor speeds.
has an overheating device (thermal limiter) that will open the resistor coil when the temperature reaches approximately 184°C (363°F) , interrupting the blower motor operation in all speeds except high.
is serviced as an assembly. The thermal limiter cannot be reset and is not serviceable.
Depending on the blower motor switch position, series resistance is added or bypassed in the blower motor circuit to decrease or increase blower motor speed.

 

[2006Overlander]

Update:

FIXED! FIXED! FIXED!

With the help of your brainstorming and another genius Facebook Group member he was able to diagnose my Master Auxiliary Switch Panel. It didn’t reach the required ohms for prescribed S4 test in your manual. I also went ahead and removed the 2nd Row climate controls and installed it to the front plugs for testing and bam! Rear AC kicked on. Beyond stocked and beyond grateful for your help in this matter. Went ahead and ordered a replacement part from ebay and from then on I will button it back up.

Again, Mahalo for your help! I appreciate it.

Attached image of broken part

 

[whtbronco]

Well I be darned. That is wonderful, congrats on resolving it. Thanks for the detailed follow-up too. It kind of looks like that front/overhead switch melted just a bit.