EATC o-ring repair - How to... with pics.

[04allstock]

Okay. I replaced the blend door motor and have regained control of the temperature. I hate to chalk it up to coincidence that the blend door motor just happened to go bad the second I replaced the o-rings in the EATC, but whatever. Fan speed is still touchy. I have control from mid-high fan speed, but no low setting. I guess I need to set my sights on the blower motor now? How in the hell do all these things go bad at once? was it the solar eclipse??

Do I need to be looking at the blower motor? Or the BCM? Fan blows hard but there is touchy control of the fan speed, with almost no low setting.

[RF Overlord]

Blower motor is way easier to replace than the BMSC, but unless you can beg/borrow/steal a spare of each, it's difficult to know which is bad. Since the BMSC outputs a PWM signal, it's not as simple as putting a voltmeter on it...it's also possible the fan speed control in the EATC head unit is bad.

[12odee]

My face is now enjoying getting blasted by the hot/cold air of my choosing.

[B4Real]

Thank you sooooo much ! I was told by a local garage 2 years ago it was the actuator door. They were going to charge me nearly 500.00. I followed your suggestions and my cousin and I was able to fix the problem by changing out the 4 o rings. It didn’t matter Orelieys sells them for a dollar a piece. I was glad to pay it! Thanks again!


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[sspmustang]

I realize this topic is nearly 10 years old, but I also recently ran into the situation where the air was only blowing cold thru the defrost and decided to try the O-ring fix. The parts themselves were a whopping $2.34 from Grainger for a bag of 100 red silicone ones.

Oddly enough, simply replacing the O-rings did not actually address the problem. It took running the self diagnostic test after re-installing the EATC and viola!, air started blowing nice and cold thru the vents.

Thanks to everyone who offered their assistance in this thread. It would be nice if all of the Marauder fixes were as cheap and easy, and if anyone needs some, please PM me, I think I now have a lifetime supply.