RobG

Thanks!!

Okay, a scanner... Is this a Dodge-specific tool or can I rent/borrow one from Autozone or someplace? Sounds like I may just want to order that sensor and figure out how to cut an access hole in the dash to replace it. Anybody know where it's located, physically?

On another note... I have a '96 Suburban also with A/C problems. Was working fine til recently. Since I had the guages I just picked up, I checked and it's also full. The readings are 42-ish psi on the low side and 50 psi on the high side, readings constant. The compressor doesn't kick on at all. Any idea what might be the problem there? The instructions that came with the guages say possibly a bad compressor.

Rob

carpenterje

I just had to have my a/c worked on. They had to order some parts cause they said the lines were clogged. A/C worked great for a few days and now I have to turn up the air full blast to get any effect out of it. When I bought the truck on level 2 it would just about freeze you out of the cab. I know I hear people say we have the best truck, the only thing good about these trucks is the cummins. After all the problems and different dealerships I've been too, across the country. They just don't seem to get it right. It is funny how I thought I had one of the best trucks out there, but it spends more time in the shop than I get to enjoy. All ready tried to lemon law the thing, has to be 3 for the same thing. I have 5 Marines that work in my unit with me that have Ford PowerStrokes,1 a Duramax and haven't had any problems with them. I work with these guys everyday so I see how they drive their trucks everyday to work while mine every couple monthes is back to the shop. And you know what the real sad part is when I deployed overseas, I saved up my money for a down payment on this truck I have. And DC's got it, while I got the problem truck. What a waste of money. I should have took that money and flushed it down the toilet. I probably should've took that money got a ford and transplant a cummins in it. Just venting.

2500

why in the world are you still screwing with the AC yourself?

if your warranty is bumper to bumper... I'd hope to shout a $1,600 warranty better cover everything! I'd be reading the fine print and making the dealership FIX the problem(s).

as a side note: some vehicles have a thermal expansion valve (TXV) but most have a fixed orifice (due to costs) to meter amount of liquid. fixed means AC doesn't have a way to regulate amount of liquid allow through orifice. hence need for a sensor to kick off compressor.

TXV work by using a bulb filled with refrigerant. bulb is attached to heat exchanger, depending upon temps refrigerant will close or open TXV regulating amount of liquid accordingly.

by the way I thought cat_diesel's description of how a AC system works was excellent! not everyone will go to that much trouble explaining how things work!

if you have a few spare minutes.... lookup "superheat" and "subcooling"

most accurate way to dispense correct charge is to pump system to a vacuum. then dispense to the oz, exact amount system calls for. unfortunately this requires yet more gear...

vzdude

The scanner I would use would either be one that Dodge garages use ( Starscan or DRBIII) or a Snap On scanner. I have access to both thankfully. I really doubt that the one from Autozone will be able to get you the sensor readings you need. As to replace the sensor unfortunately.......
REMOVAL

1. Remove the HVAC housing and place it on a workbench (refer to 24 - HEATING & AIR CONDITIONING/DISTRIBUTION/HOUSING-HVAC - REMOVAL).
2. Remove the wire lead for the evaporator temperature sensor (2) from the retainer located on the HVAC housing (1) and disconnect the sensor connector from the HVAC wire harness (3).
3. Remove the lower half of the HVAC housing from the upper half of the HVAC housing to gain access to the A/C evaporator (refer to 24 - HEATING & AIR CONDITIONING/DISTRIBUTION/HOUSING-HVAC - DISASSEMBLY).
   
   
4. Carefully remove the probe of the evaporator temperature sensor (1) from the fins of the A/C evaporator (2).
5. Remove the wire lead of the evaporator temperature sensor (3) from the upper half of the HVAC housing (4).

As for the suburban, check all the fuses. Then check the low pressure switch - IIRC it is on the receiver dryer on the passenger side of truck - it should have continuity across it when unplugged - with enough pressure in the system. I don't think you have enough freon in the system by what your readings were. Sounds pretty low. Add a can of freon and see then. You will have to unhook the battery I think to reset the A/C head. It will disable the compressor if it sees low pressure for long enough. It has been awhile since my GM days, but thats the best I can recall! Try all that, and let us know! Good Luck.

Andy

CatDiesel_762

Rob,

Thanks for the update. However, I am still going to stick to my original diagnositic opinion. I believe it is the TEV switch (Thermatic Expansion Valve Switch). This switch is what causing your compressor to cut out. Your readings seem fine for a R134A system, since different refriderants have different pressure.

Your A/c will only work when the compressor is turning and the refridgerant is cycling through the system. This is why we have the TEV, since the refridgerant can freeze up the evaporator and prevent the A/c system from working efficiantly. That is what is causing the slightly warmer than previously cooled air to occur at the vents. That is why your compressor cycles to thaw the evaporator to allow the evaporator to have a greater surface area for air to be cooled. Just like your radiator and thermostat on the front of your truck cycles to keep the engine in optimal temperature for combustion.

As for your sububan, I am thinking compressor probably shot. Otherwise the condessor's cores fins are all buged up. You might want to try this on the Dodge too and clean and straighten the fins on the condessor. Not to metion, it a cheap fix to keep the A/c system working at its peak.

I slso been doing some looking on line, and came across this web page. I think you might find it informative with your new gauges. Some pages are still underconstruction and is a little confusing. However, most of it is easy reading and very helpful. There is pictures too.
(This is not my site, nor do I know who owns it.)
http://www.autoacrepairs.com/index.html

Shawn

CatDiesel_762

I just saw your other post on the suburban. I agree with VZdude and the system is probably low on freon. That web site I mention earlier noted that GM tend to have a lot of compressor failures. Look for oil at the A/c compressor or on the hood in the same location and you will find your leak.

Shawn

RobG

Shawn:

Thanks again! If it's the TEV switch, where is it located? Is it back behind the dash too?

Rob

CatDiesel_762

Unfortunately it will require removal of the HVAC Housing from under the dash. If you look at earlier post by Vzdude. You can see with the pictures how much a pain the the EVAP Switch or TEV Switch (as I call it) HVAC is. Before removal of the HVAC housing you will need to recover the refridgerant from your A/c system and drain the antifreeze from the truck in order to remove the HVAC as a unit. Do a search on TDR.com about blend door replacement in the non-engine driveline forum. The first page has all the photos of the HVAC removal from a third gen truck.
http://www.turbodieselregister.com/f...-pictures.html
This post will have pictures and kind of guide you through the process up to the evaporator, if you want to go this route by yourself.

Shawn

Grit Dog

I don't have anything useful to add, other than I'm amazed once again at the sheer amount of knowledge and helpfulness that is available on this forum.
If I have an A/C problem I know who to call!

2500

looking like this is beyond most DYI'ers. purely due to tools needed.

at min... besides gauges, need evacuation pump/tank to remove refrigerant. then a good vacuum pump before installing new refrigerant.

here's my setup...

OX1

Was that through Chrysler?? A buddy just got dealer cost (from his uncle) on the top of the line (supposedly) Chrysler warantee on his 05 and he claimed 2400$ (retail in the 3200$ range).

RobG

Yes, it's a Chrysler warranty. The dealer told me it was the best one availble for my truck, so maybe there are better ones. BTW it was $1800 not $1600, I was wrong.

Now for the VERY INTERESTING NEWS... I was waiting a few days to ensure I was right, and I think I am.

I FIXED THE PROBLEM MYSELF!!!!

It wasn't freon...
It wasn't blend doors...
It wasn't the compressor or clutch...
It wasn't the expansion valve...
It wasn't the evap temp sensor...

The dealer is a freaking IDIOT and I'm going to be filing a dispute with my credit card company over the $231 they charged me to add freon that was unnecessary.

From the very beginning I've been saying this was clearly an electrical problem. I told the dealer this and described it thoroughly. They obviously chose to ignore me.

The problem? THE ELECTRICAL CONNECTOR TO THE DASH CONTROLS WAS LOOSE.

Yep.

I had the dash panel off because I was wiring up the in-cab control for my airbags, and so I unplugged everything (cig lighter, A/C controls, etc) so I could set the panel aside. Well, when I went to unplug the wiring harness to the A/C controls that was nearest the A/C button, I didn't have to push in a little button... it just came out. I didn't think much of it at the time, but made a mental note.

So when I put it all back together, I paid attention when I plugged that one back in... it went in firmly with a CLICK. Hmmm. Could it be?

That was three days ago. The A/C has not hiccuped once since that time. The A/C blows good and cold, but no colder than before the dealer supposedly added freon, which tells me it probably didn't need it and with my luck they probably overfilled it.

I want to give a HUGE THANKS to everybody on this forum for helping me through this... you guys really are awesome. I've learned a LOT about A/C... and I gotta say I'm VERY pleased the fix was so simple!!! But at the same time, I want to strangle the [censored] dealer.

Rob

rockdonon

WOW !!! Between this story and "CARJACKED" by Hoss.....who needs to go to the movies for entertainment? It's right here @ DTR ! It is awfull however that people have to get Jacked Around by most Dealers and extended warranties.

azdodge

I just had the a/c updated in my 03 when it went out last summer. Dodge has had tons of problems with the 3500's a/c units. The pump, interior controls, and vent doors were all replaced under my chysler extended warranty, to the tune of $2000.00

falstaff

Never buy an extended warranty for ANYTHING. They are nothing but profit for the dealers.

Always bad for the consumer.