Acura MDX SUV Forums banner

1 - 7 of 7 Posts

·
Registered
Joined
·
7 Posts
Discussion Starter #1
Hello: The weather here in the NE is just starting to warm up so I haven't used the AC in probably 4-5 months. When I fired it up last week it was blowing warm.

I assumed that since the car has 129,000 miles and is now 7 years old and it has never had any refrigerant replaced, that this would be my problem.

However, after searching these forums, it seems like there could be several possible issues. Top three appear to be #1 Bad clutch relay. #2 Clutch gap too large. and #3 Low refrigerant.

The easiest one to address to me was the relay. However, I am having a hard time figuring out which one it is! I have attached a pic of my relay box (the one under the hood, passenger side). Can someone tell me which one the AC clutch relay is? Also, I have read that the fog light relay is in there somewhere as well and is the same type of relay. Posters have stated that a quick check would be to to put the fog light relay into the place of the AC clutch relay to troubleshoot. Can someone also tell me which one of these is for the fog lights?

Also, how does one tell if a relay is bad other then shaking them and seeing if anything rattles around?

I am having trouble seeing/locating the clutch itself to see if it is engaged when it is supposed to be. I think I know where it is but I'm not sure. If anyone has a picture that would help me locate it, I would greatly appreciate it. What I can say is that when I am in the car and I turn the AC on, the engine does seem to react appropriately (RPMs seem to drop and jump back up when I turn the AC off again, just as it sounded when the AC was working properly). Is this an indication that the clutch is engaging normally?

Finally, I did attach a gauge to the low pressure AC port and it goes up to 95 when the engine is off and almost off the chart to 120 when the engine is on and the AC is on Max. What is the significance of this?

I know this is a lot, but I would greatly appreciate some help with this to see if I can avoid a trip to the shop to save some $ and keep this a DIY job. If not, I'll bite the bullet and do so.

THANKS SO MUCH!
 

Attachments

·
Registered
Joined
·
336 Posts
If I'm not mistaken, on the underside of the lid for the fuse box is a diagram of the fuses. That should tell you which relay is which. I replaced my relay last summer, but I don't recall which one it was. Be careful pulling them out as it is easy to break the plastic housing.
 

·
Registered
Joined
·
7 Posts
Discussion Starter #5
The diagram on the under surface of the box is extremely confusing. No help to me at all really. I went ahead and replaced the "third relay over" as someone mentioned in another thread (his was an 07 and mine is an 09 but I assumed they are the same within the same generation MDX). I then tested the pressure on the low pressure port and it was now "in the green" at around 40. As I noted in my original post, it was 95-120 in the red before). It is pretty cold here (low 50s) so I really couldn't see if it was blowing cold even at the Lo setting. However, the air does show a distinct difference when I go form AC off to AC on. It is less humid and possibly a little colder.

The fact that my psi went down significantly with the new relay tells me that my AC clutch was probably not functioning due to a bad relay.

Hopefully it will warm up a bit and I can test it out.

Thanks!
 

·
Registered
Joined
·
336 Posts
Sounds like you got it fixed. I remember the air being very humid when our relay was bad. And with the bad relay the A/C didn't turn cold until 20 minutes into running. The new relay fixed all of that.
 

·
Registered
Joined
·
5 Posts
Sounds like you got it fixed. I remember the air being very humid when our relay was bad. And with the bad relay the A/C didn't turn cold until 20 minutes into running. The new relay fixed all of that.
New relay fixed mine too. thanks for the post
 
1 - 7 of 7 Posts
Top