M-30 VG30E, airconditioner works good sometimes...

[Mikoriad]

I've had the compressor checked and also the system pressure, no leaks ans everything seems to be in proper shape. The problem is the a\c only works sometimes. When it does start working it's great, the air is very cold and things operate normally. The problem is once i turn the a\c off it won't get cold again if i try and turn it back on. I can hear the compressor kick in, and even the cold lines get cold like normal. After trying the a\c everytime I get in the car, sometimes days later, it will suddenly get cold and start working again. Ive heard it that it was the blend door, but the code does not come up when i do a self diag. Any Ideas!! It's really hot...

[DAEDALUS]

Blend door sounds like the most plausible explanation given the symptons. Could be a mechanical defect. Do you have a service manual?

[Mikoriad]

I did print out a self-diag instruction page. It went through each test and no faults were found. I've also been told by a few mechanics that it's rare for a blend door to work only somtimes, usually it's either broke or not. I'm pretty lost, and i can't spend the money to take it to a dealer. Is the blend door accessable by taking the glove box out and going from there? Anyways...uhhh no I don't have a manual.

[DAEDALUS]

Sorry to say I don't either so I can't help too much. Some cars require dashboard removal, some don't.I agree a door working only some of the time sounds strange, but the number of suspects is limited. If the line is cold the evaporator is almost certainly cold too. The other possibility is that there is an intermitent electrical fault with something that is not checked by the self-diagnostics.

[Mikoriad]

I think you're on to something as far as a possible electrical prob. Just this morning I pressed the on button for a/c, the air cooled nicely and everything was working fine. About 2 miles down the road the climate control display, blacked out for about 15 seconds. While this happened the air also stopped blowing. There was nothing wrong with tthe drivability of the car, it only seemed to effect the fans and the climate display. When the power came back the a\c wasn't cold anymore, felt like it was stuck halfway between cold and hot. The a\c started working fine about an hour later. I may dive into the dashboard just to see what I can find. Maybe a chaffed wire, or something block the blend door. blahh... it's pretty irritating, temps are breaking into the hundreds here in Georgia. Thanks for the help, let me know if you think of anything new.

[DAEDALUS]

If the problem is isolated in the AC controller at least you won't have to tear everything apart to get to the air mix door. Either send the unit somewhere to get it inspected/fixed or pick up a known good used one for cheap.

[Mikoriad]

Finding a known good one is the problem. I've acutally thought of swaping the climate control section. These M30's are damn rare to find, especially one I can take parts from and test. I've seen 2 M-30s in the junk yards around here, they were both stripped to damn near the frame. I've had an eye out for them since I got the car.

[M30 Steve]

Hello mikoriad

i have had an on going problem with my ac /heat control. I replaced my controller last year they are known to black out. I could hit the dash and mine would light up. after replacing the unit I had poor heat/cool response. As it was -20 here i did a quick fix, i disconnected the mix door rod and connected a manuel rod i could reach by hand(right side of center console) now I reach over to adjust cold/ hot function. What I have done is bypassed the auto climate feature. The reason the auto control will not work is most likely one of three sensors not working. There are several post on this sit about a guy who rebuild theses units, do a search for climate control. The other trick might be to find a manuel control, some M30's came without auto climate control , meaning they had a fan control (speed switch) then a manuel lever for temperature. I was able to purchase an auto control at car parts.com for $40, I was lucky the part worked for me. Using my manuel system now I get cold AC and super hot heat. I hope to troubleshoot the system someday and get the auto feature back. The air door is easy to access through the center console, just pull the radio out. I do have a FSM for the car, let me know if I can send info. The diagnostics on this auto climate stuff are pretty involved. I am a novice (backyard mechanic) but I have learned a bit about the M30Thanks Steve

[Q45tech]

Call T3 South Cobb Drive, we have 2 - M30 junkers and experts to diagnose.........plus the owners has an M30 convert we keep going. 404 - 794-7700.