EATC Woes (Replaced O-Rings)

PyrBliss

PyrBliss

New member
Just picked up my first Marauder. AC didn't work and nothing came out of the vents (at any fan speed). Going through this before with my Grand Marquis, I grabbed a new blower resistor motor. Yay got air coming out of the vents again. Crap only defrost though. Grabbed some flurosilicone 007 size O-rings and much to my surprise I still only have air coming out of defrost?

I switched the EATC from my GM which had the same O-rings replaced and voila - I have air from all vents again. Do EATC just go bad? Ran self-test. No codes? I'm stumped. Before I buy a new one, I just want to make sure there isn't something else I should be trying? It has to be the EATC itself since I switched it with a working unit and it solved the problem. Thank you in advance.
 
I thought about that. Not sure what though since I successfully fixed my GM EATC the exact same way with the same parts. I will pull it out and re-do. Thank you.
 
Thanks. I will pull it out tonight after work and give it a more thorough look over. Will report with my findings.
 
I've heard of the internal vacuum manifold, the part the solenoids attach to, being porous or cracked. Someone here fixed theirs with epoxy.

Or it could be an electronic issue and the solenoids aren't being triggered.
 
Chayton said:
I just changed my o rings and it didnt work
Click to expand...
What was the original problem? Usually when it's the o-rings you find the system changing from dash vents to defrost when accelerating or when going up a hill, then restoring to vents when you let up on the gas. If it's stuck on defrost full-time, then you have other issues, like the OP.
 
Update:

Discovered a spring missing in one of the vacuum actuators. Not sure how I missed that when I initially replaced the O-rings. :rolleyes:

Now I just have to find a new spring....
 
Fastblackmerc............

I sent you a PM but my message box says nothing was sent??? Just let me know if you get it or not. Thanks.
 
I just took my EATC apart. My MM is a parts car I saved from oblivion, was being parted out when I bought the whole thing. There was an EATC shoved in the slot. Must have been a trade from someone else during the part out.

No air control, only full defrost. I took the solenoids apart, changed the O-rings and one spring was missing. Weird. So I bought a non-operational EATC from ebay to get the solenoid spring I needed and for any other parts when I opened mine up. $20 bucks.
 
RF Overlord said:
What was the original problem? Usually when it's the o-rings you find the system changing from dash vents to defrost when accelerating or when going up a hill, then restoring to vents when you let up on the gas. If it's stuck on defrost full-time, then you have other issues, like the OP.
Click to expand...

It is stuck on floor/defrost full time. What should be replaced?
 
The floor and defrost functions share a common vacuum motor. You can try taking a small piece of vacuum line and jumpering from the black line (vacuum source) to the yellow line and see if you now have defrost-only and the red line to see if you now have floor-only. If not, then the vacuum motor is probably bad. If it does work, then the issue is inside the control head.

You could also try the control head from your Sport if it has EATC.
 
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