Lincoln Forums Navigation:

Can an AC Compressor fry an ECU

Ralphy2011

Junior Member
7
0
1
So as this title might suggest, I'm in a bit of a pickle.

2003 Lincoln Town Car Executive

So I took my car into a shop, I've been going to for years and I trust the work they do, to get my AC recharged to see if i needed a compressor or not. The system was empty and the can I put in wasn't enough to kick the system on, so I figured a professional evac and recharge machine could get it going. Well turns out, it took the full fill, then the compressor ran for a split second, shorted, and the ECU was dead. Like not an ounce of communication through the OBDII, no start, nothing. So the shop had to source and exact match replacement ECU and reprogram it to get the car going.

Quick side note, this all happened today and they haven't gotten it going yet, they said it should be running tomorrow.

I'm a little frustrated at this because it went from a standard 50 dollar fill (which they were already cutting me a deal on) to a rather expensive repair (I haven't got a final price yet but my guy there said he will take care of me, I'm just assuming because new ones cost around 400 dollars that I'm going to be out more than 50 bucks).

My first question would be this. Can a professional AC charging system fill the high side of the system without running the compressor? It was my understanding that you could only fill an AC system from the low side. Now that could be from the cans you can get from a parts store because I know those can't handle the high side pressures, but i wanted to know if that's the same rule for professional systems.

My second question is one about Ford's engineering. From what I've been told by this shop, and from a certified Ford tech (which may make this question kinda dumb because the tech should have the right explanation), is that Ford "in their infinite wisdom" (Ford Techs words) decided to run the ECU and AC compressor off the same fuse, essentially running them in parallel. I guess I'm just asking for confirmation on that?

My third question is more of a philosophical question. Should the shop pay for the part that was damaged as part of a standard repair? or at least discount it and eat some of that cost? I guess it would come down to how the part ended up getting damaged. Like if it was a non-standard procedure that was used to get the compressor running. Or if it was just some fluke from a bad compressor and poor design.

Anyway I'm rambling because of my frustration. ill hopefully be getting a call tomorrow saying the car is fixed. Thanks for reading!
 
Last edited:
44
0
0
Sound more like they just blew a main power fuse. While the ECU can shut off the compressor through a relay they are not direct wired I don't believe you can push enough feed back up the loop to "FRY" an ECU. AS to filling the system. you can fill, that is add the correct amount of refrigerant to a system through either hose! The system is a closed loop.
 

mark0101

Junior Member
11
0
1
First of all, if the system needed a full recharge, your a/c system has a leak. That 50 bucks you just spent on filling it will just leak out in the air. Might as well take that 50 and burn it. You first need to find the leak, mostly likely underneath the accumulator/drier that tend to leak with these cars.

I am not sure if the ECU and compressor is on the same fuse or what not but I would say they are not linked.
______________________________
 
44
0
0
did they check all the fuses? there are some in the engine bay and some under the dash. There is also a relay for the PCM. A ford tech would know that the lincoln uses a PCM not and ECU. also the ac is fuse #2.6 while the fuse for the PCM is #2.12 I tried to attach a diagram of the under dash but it won't take.
 
Your email address will not be publicly visible. We will only use it to contact you to confirm your post.

HTML

Top