Chrysler minivan a/c mechanically good, but no cold air

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N2Audio
Posts: 5
Joined: Tue Jun 13, 2017 1:45 pm

Chrysler minivan a/c mechanically good, but no cold air

Postby N2Audio » Tue Jun 13, 2017 1:54 pm

Hello first post here looking for some guideance.

One day a/c was great, next day hot air.
I have been through most of the basics. It had 100psi static pressure on the low side which told me the compressor should have been engaging. So I shorted the power contacts at the relay and the system ran and cooled.

I tested the relay with my DMM and it checks out. I also swapped it with a relay from a different accessory and got no change.

Had a shop do a basic a/c service -- it was slightly over charged and corrected, no leaks were found.

I have tried a new pressure switch, no help.

Where should i look next?

Thanks,
Justin

04 chrysler town and country 3.8l 188k
Dougflas
Posts: 189
Joined: Mon Apr 18, 2016 6:10 pm

Re: Chrysler minivan a/c mechanically good, but no cold air

Postby Dougflas » Tue Jun 13, 2017 4:02 pm

Take a relay apart and use it as a test. Make sure the connecting pins are making contact. You can use a clip lead to make and unmake the relay connections. make SURE you are on the correct terminals.
N2Audio
Posts: 5
Joined: Tue Jun 13, 2017 1:45 pm

Re: Chrysler minivan a/c mechanically good, but no cold air

Postby N2Audio » Wed Jun 28, 2017 6:53 am

Here's the status...
Compressor good
Clutch good
freon good
relay good - 13.8v at pin 30, 13.8v at pin 86 when a/c switch is turned on.
fuse good
pressure switch good and 5v supply and pressure sensor lead have 4.9 and 1.05v respectively.

Still no cold air (compressor does not engage).

Again, I can jump the 30/87 terminals at the relay socket and the system will turn on and cool.

I have disassembled the fuse box down to the board -- there is no evidence of a burnt connection or any wiring deterioration. I would think if it's something as simple as a terminal that has "opened up" at the relay a simple wiggle test would make the connection, but it doesn't.

Here are links to the a/c wiring if anyone cares to have a look.

https://www.2carpros.com/images/questio ... iginal.jpg

https://www.2carpros.com/images/questio ... iginal.jpg

It's been a fairly mild summer so far here in KS, only a few days in the 90's, but this won't go on for ever. With a 30 min one way commute to work and a 9 y/o kid playing a lot of baseball riding home in a sauna isn't fun for anyone.
su2200
Posts: 1
Joined: Mon Jun 26, 2017 4:26 pm

Re: Chrysler minivan a/c mechanically good, but no cold air

Postby su2200 » Wed Jun 28, 2017 4:58 pm

N2Audio wrote:Here's the status...
Compressor good
Clutch good
freon good
relay good - 13.8v at pin 30, 13.8v at pin 86 when a/c switch is turned on.
fuse good
pressure switch good and 5v supply and pressure sensor lead have 4.9 and 1.05v respectively.

Still no cold air (compressor does not engage).

Again, I can jump the 30/87 terminals at the relay socket and the system will turn on and cool.

I have disassembled the fuse box down to the board -- there is no evidence of a burnt connection or any wiring deterioration. I would think if it's something as simple as a terminal that has "opened up" at the relay a simple wiggle test would make the connection, but it doesn't.

Here are links to the a/c wiring if anyone cares to have a look.

https://www.2carpros.com/images/questio ... iginal.jpg

https://www.2carpros.com/images/questio ... iginal.jpg

It's been a fairly mild summer so far here in KS, only a few days in the 90's, but this won't go on for ever. With a 30 min one way commute to work and a 9 y/o kid playing a lot of baseball riding home in a sauna isn't fun for anyone.


You get clutch activation when you jumper the relay power contacts so the wire from relay to clutch and clutch coil are good. The power train control module supplies ground for the clutch relay. The pcm monitors the pressure switch and if it is in the correct range the pcm pulls the relay coil to ground closing the contacts and sends power to the clutch coil. So check the wiring from relay to pcm (ltblu/org)and from pressure switch to pcm. You say the pressure switch is good, but is it sending the correct voltage to the pcm? Check the connectors at the pcm and pressure switch. You can jumper to ground the relay pin 85 and see if the relay pulls in and the clutch pulls in. If yes then wiring to pcm, pressure switch wiring to and from pcm, pcm and pressure switch are the suspects.

Hope this helps.
Roy
N2Audio
Posts: 5
Joined: Tue Jun 13, 2017 1:45 pm

Re: Chrysler minivan a/c mechanically good, but no cold air

Postby N2Audio » Tue Jul 11, 2017 9:50 am

Had it diagnosed as faulty evap temp sensor. Repair price was not reasonable considering my finances and the value of the van. I will either live w/o a.c. or figure it out myself. I'm having trouble finding much info on this sensor other than the tech mentioning the dash has to come out.
I cannot find a listing for evap temp sensor at rock auto. Is it part of the evap coil? I don't see any elect connectors in photos.
User avatar
Cusser
Posts: 278
Joined: Sun Apr 24, 2016 6:29 am

Re: Chrysler minivan a/c mechanically good, but no cold air

Postby Cusser » Tue Jul 11, 2017 11:04 am

N2Audio wrote:Had it diagnosed as faulty evap temp sensor. Repair price was not reasonable considering my finances and the value of the van. I will either live w/o a.c. or figure it out myself. I'm having trouble finding much info on this sensor other than the tech mentioning the dash has to come out.


Hmmm - many vehicles had a de-icer switch on the OUTSIDE of the evaporator box, and a sensor sticking through a small hole to the inside of the evaporator...maybe one of those could be used instead of factory one IF it is true that the dashboard must come out to do this. On my 1988 B2200 truck, just the glove box needs to come out to access this.
71403
Posts: 21
Joined: Fri May 27, 2016 12:46 pm

Re: Chrysler minivan a/c mechanically good, but no cold air

Postby 71403 » Tue Jul 11, 2017 2:31 pm

Is the van auto or manual temp control? ATC the evap sensor is on the TVX block underhood, manual temp control is in the evap case behind dashboard.
N2Audio
Posts: 5
Joined: Tue Jun 13, 2017 1:45 pm

Re: Chrysler minivan a/c mechanically good, but no cold air

Postby N2Audio » Tue Jul 11, 2017 9:25 pm

It's auto climate control
71403
Posts: 21
Joined: Fri May 27, 2016 12:46 pm

Re: Chrysler minivan a/c mechanically good, but no cold air

Postby 71403 » Wed Jul 12, 2017 7:41 am

If it's ATC the manuals show the evap temp sensor is on the TVX block underhood. Still a bit buried but better than dash R&R.
N2Audio
Posts: 5
Joined: Tue Jun 13, 2017 1:45 pm

Re: Chrysler minivan a/c mechanically good, but no cold air

Postby N2Audio » Thu Aug 03, 2017 10:26 am

Thanks for the tip that the sensor was on the expansion valve. The dealership didn't catch that. They sold me the wrong part.
Only after quite a bit of research it became clear the sensor is not sold separately, it is PART of the expansion valve.
Also, the OEM valve is ~$120, but using the OEM p/n I was able to find an aftermarket valve for $32.
The job itself isn't that difficult. I had a problem stripping threads when I took the bolts out that hold the valve in place as they thread into aluminum. Luckily, once I cleaned the aluminum off the bolt there was enough thread remaining in the AL block to allow the bolt to tighten.

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