AC immediately shuts off
 

Hi all

I've searched the site before posting and have found similar problems but not exactly the same as mine

Many have had no blower with dead AC but my AC actually starts for a brief instant then immediately cuts off.

It appears to stay on as far as the temperature setting shows but the recirculating light is off and there is no compressor action or blowing.

Both fans under the hood both come on for that brief startup moment and then turn right off.

So basically it's the AC starting like normal but then turning right back off.

I've checked the fuses and relays and hope I haven't overlooked any but they all seem ok.

I'm stymied so any suggestions would be most appreciated!

Thanks!

Rick

Try the A/C on board self-diagnosis:
Attachment 66923


Attachment 66924

Hi Skirmich

Thanks so much for the quick reply!

I didn't know that test was available. I gave it a try but to no avail.

I followed the directions exactly and tried two different times but the temperature screen stayed blank and returned no codes.

Am I to assume the problem lies somewhere else since I got no codes? Any other direction you can point me in we be most appreciated.

Thanks for your help!

Rick

P or s model?

Does the heater work?

Before this happened was the ac running warmer than normal? If so then you're just low on freon. The system will shut down if freon pressure is below 28 psi.

How have you checked the relays? By multimeter or just by eye?

@01acls: Nothing happens with heater or high temp settings. No blowing at all but the selected temp still shows like its on but nothing is happening. Excuse my ignorance but I'm not clear on what you mean by P or S model.

AC was running cold and freon is full

@thoiboi: I checked the relays by swapping them since they appear to be the same type and everything else is working just fine with the car. Is there a better way to check and rule out relays?

https://cimg0.ibsrv.net/gimg/acurazi...1c652faefc.png


https://cimg2.ibsrv.net/gimg/acurazi...2d7337d3f2.png

Pressure Switche is located on the dryer.

Thanks for this latest batch of info! I'll give it a try tomorrow and report back

Ok gang here's my results thus far.

1. Tested voltage and got 4.9 so close enough.
2. Checked continuity between terminals on switch and there was no continuity
3. This took me to step 11 to see if pressure was in spec. I only have a simple gauge that came on a can recharge kit. Not sure how accurate it is. It shows more than enough pressure at 100. Mind you this is an iffy gauge and the ac has been operating just fine the past year so it's not been overcharged in that time.

So now my dilemma is do I assume it's within specs and replace te switch OR assume its not within specs and "repair the AC pressure problem ", whatever that is as what all it entails?

I feel like I'm zeroing in on the issue thanks to all your advice, now if I can get to the final solution I will be a happy camper again!

So what in your learned opinion is my next step?

Thanks again for all your help!

Rick

Q: the 100 psi reading... what was ambient temperature?

One more thing I meant to ask. Is there a way to bypass the pressure switch so I can engage the compressor and keep it going in order to get a proper pressure reading?

I think I read somewhere once that you can't get an accurate reading without the engine and compressor running. Not sure if that's accurate info though since I'm a bit of a novice.

Yes just jump/bridge the pressure switch connector... the blue/red and the yellow/green wires.

If the clutch stays on I would say you've found your problem but check the pressure readings to make sure it with in specs.

If it's low... add. If high... take to ac shop to recover the excess.

Do not run ac if higher than normal... you will damage the compressor.

Hot today, thus the need to get the AC fixed ��
Ambient temp is about 85. Reading was engine/compressor off.

Heading outside shortly to give it the jump test and report back with that reading.

I truly appreciate your help and patience!

That's about the right temp. Your switch is bad. Good job.

Just did the old jump with a paper clip trick but no luck. Same original problem still.
Turns on for a couple of seconds and turns right off.

So since I did the bypass does that mean the switch is good and the problem is elsewhere? It seems unlikely its low on freon with the reading I'm getting. It would be nice if that was the problem though since it's a cheap fix. I just don't want to toss more freon in and possibly overfill it

So close yet still so far

Lol duf.

No switch is ok then.

Check the following....


https://cimg8.ibsrv.net/gimg/acurazi...5d216fbe26.png

Check clutch relay fuse: # 58 (20A) under hood.

Activate the ac clutch by jump the relay wires red and white. If the relay is marked it will be terminals #1 & 2.

Year/model-premium or s type?

https://cimg0.ibsrv.net/gimg/acurazi...885543aec1.png


https://cimg1.ibsrv.net/gimg/acurazi...0cb801865a.png


If all of above check out the move on to climate control.

Low on feon is still a possibility. Normally one would rule that out by vacuuming then filling to proper weight.

Wow, thanks man for all the new info. It just started pouring rain and I have no carport or garage to work under so I'll have to wait it out to try your suggestions.

By the way I'm in Florida and the car is a 2000 TL 4 door with NAV. Have questions about the NAV too but that can wait for another time

215,000 and still going strong though

Op did you check this thread out below...? Specifically item #3 & 4?

https://acurazine.com/forums/problem...ir-diy-775458/

Thanks I'll check that as well. I'm hoping it doesn't just address a non working blower that isn't pushing through the cold air from the compressor. I have nothing once the quick kick-on and kick-off happens.

With your most helpful advice I'll solve this mystery yet!

This actually just happened to me last week. A/C comes on for a split second, then off. The blower will not blow air at any speed. Diagnostic DTC shows indicator 'N' - problem in the blower motor circuit.

I'll just add it to the list..

AC immediately shuts off
 

Check the aC clutch relay..

See Post No. 22.

I have had the same problem. Took my mdx to a shop with a machine that vacuums and refills the freon and oil.

He had a probe that said the ac climate control was bad. I put another on and it still doesn't work.

You should try replacing the AC relay with another (same type) from the fuse box (swapping places). Also it could be a defective ac clutch. Assuming your ac is not low on freon.

Are you about the relay under the hood?

Yes

Thanks!