This is my second time asking for help whithin the last 3 days. On my last thread i asked about oil in the intercooler. Now i have two issues that have surfaced while up here in the mountains (it's snowing, HARD, i love it).

1.)My rearview mirror is wigging out (temp and compass). It works great for one second and then it goes through a reset mode, flashes a couple of times, then starts working again.

2.):mad: This one really pisses me off. My A/C won't turn on because it's bellow 40 degrees outside. What in the Censored hell were they thinking when they programed our trucks to operate like that. If i want my A/C on then gosh darnit let me turn it on. In California the weather in general is humid, but when it snows it gets really humid. I'm sitting in my truck with 4 hot sweaty skiers and now i can't see out of windows. What gives? I had to wait 5 minutes so that i could see out the front windshield, barely. Is there a way to reprogram this with the tech II or do we have to have fingers make another stick?

I usually try to figure things out on my own but this weather can't be duplicated in san diego. And you know what the dealers gonna say. Thanks in advance.

Putting it in defrost will turn on the A/C compressor. It cools and dehumidifies the air then reheats it so that it blows hot, dry air on the windshield and side windows.

Well if it's "supposed" to turn it on, it didn't. I stood in my driveway with the hood up looking at my compressor and it never engaged. What's funny though is on the way down the mountain tonight right at 40 degrees my A/C snowflake appeared, I just rolled my eyes saying to myself what the %$#&. This truck is starting to get on my nerves. The Edge never worked properly. It's been back to the dealer 10'xs since i bought it in Feb 2004. Injectors, headliner, windshield molding, reflash, 4X4 reflash, Tailgate straps, fuel filer, now the intercooler duct is leaking oil on my driveway, the rearview mirror has a glitch. I can't turn on my a/c to take the moisture out of my cab because it's bellow 40 outside. The truck barely has 10,000 miles on it. What's gonna happen when i buy a 26 foot enclosed with all my toys in it and my family in the cab with me. Over heat. you know what really pisses me off? I'm sick and tired of my truck being taken apart and put back together. I used to turn a wrench for a living and i know what happens when something gets taken apart and put back together to many times. I usually SELL IT. I hope this is my last trip to the dealer for a long time. Thanks for listening to me rant and rave, I really enjoy driving my D-Max and i have a great deal of pride whenever i step up and get in, but i'm starting to ask myself, at what expence.

Regardless of what you take from that I am a listener and all advise is GREATLY APPRECIATED, please don't think otherwise. I'm sure I'm one of the few and far between. I have a boat load of money to throw at this truck for after market accesseries and I'm not going to do it untill these rediculous problems are remedied (for warrente reasons) ie. lift, exhaust, stereo.

At this point I would check to see if it is low on refrigerant or thinks it is low on refrigerant (i.e. bad low pressure switch). If my truck was acting like yours I would be all over my dealer which it sounds like you are. We are having our first really cold day today. I'll have to try to remember to see if the AC compressor on mine is kicking in tonight.

Good luck,
David

Thanks David,

I would have to drive approx. 50+ miles to my uncles house in Julian to duplicate the temp. Let me know what you find

Eric

Check the connector on the back of the mirror... I have seen plenty of them not fully plugged in. I second the Low Pressure switch...time for trip#11.

):h DOUGH!!!!!!

For the mirror you could try to set you zone. That's probably not the problem but worth a try.

Find current location and correct zone number from the map on Section 2 of Owners Manual;
<LI type=1>Press and hold the COMP button for five seconds until a zone number appears in the display and
Press and hold the Comp button until the appropriate Zone number appears in the display, release the button.
The A/C compressor will not come on under 40 deg F to protect itself.

Maybe the A/C is not supposed to cut on at temps below 40, but I frequently run mine during the winter to keep the seals freshly oiled. Tried it two nights ago at 36 and it came on just fine. Maybe it's not 40, just 40ish?Doug

Refrigerant is pressure relative (40 degrees ambient=40psi refrigerant pressure) The cycle switch cycles on at 40psi and off at 20psi. If the refrigerant is less than 20 degrees or so, then the compressor will not kick on, but once the engine compartment warms up, this latent heat will bring the refrigerant temp up above 40 degrees and "click", the compressor comes on. Also, does your cycle switch have a brown rubber band around the connector?

No, no brown rubberband. It states clearly in the owners manuel that the compressor will NOT engage if the temp is bellow 40.

SOOOO. what if we use a simple bosch relay switch to override the protection circutry. It's under warrentee for 100,000 miles (extended of course). What's the worst thing that could happen?

Eric

SOOO what do you guys think about a simple override relay????

Let me know

There is no "protection circuitry" Like I said in the previous post, refrigerant is temp/pressure relative. The HVAC controller uses its pressure sensor data to determine if it should come on or not. Why will the a/c shut off when the temp is cold? If the compressor is on below 20 psi, the evaporator will freeze solid, hence no airflow. That is why it must cycle off at 20 and back on at 40. To give it long enough to thaw. If it is colder than 40 degrees out, the compressor may not kick on because the cycle switch has not seen a high enough pressure to kick on. Having the compressor on when it shouldn't be could cause major problems.



Refrigerant is pressure relative (40 degrees ambient=40psi refrigerant pressure) The cycle switch cycles on at 40psi and off at 20psi. If the refrigerant is less than 20 degrees or so, then the compressor will not kick on, but once the engine compartment warms up, this latent heat will bring the refrigerant temp up above 40 degrees and "click", the compressor comes on. Also, does your cycle switch have a brown rubber band around the connector?

XR Freak Can you tell me what you had to do for your dual alternator install? And how you like the clifford auto start. Not to be off subject, but you have some nice toys already that I am interested in. If you want to contribute to my toy fund feel free!! :) I hope your problems are resolved with trip 11...I only have 2400 on my truck and hope not to encounter all the issues I see some folks having. Thanks

Max, Thanks I didn't quite understand because on all of my other vehicles, i can turn on the A/C when ever I want. That's why i was persistant.

Eric

bergeros,
Thank You!!!! I work hard but i play harder. I ordered my GMC in December of 2003 and I pick her up in February of 2004. Dual alts. is an option that came straight from the factory. However i don't think you will have any problem installing your very own, here's why. You are conected with some of the coolest people in the world on this forum:ro) . Did I mention knowledgeable:rolleyes: . When you have the money set aside and are serious about installing dual alts. Start a thread in the "ask the techs" and you will get plenty of info.

FYI each alternator on my truck puts out approx. 105 amps vs. a single that puts out approx 135. here is the link http://www.gmc.com/byo/selectOption.gc;jsessionid=FHGKNQQ0QFZ3SCSUR2USCAQ KKSHSQIJK?fromColor=true&make=gc&style=SLT&zip=75081&driveType=4WD%20&boxSize=Standard%20Box&subModel=2500HD&boxSizeId=59&makeId=012&cabSize=Extended%20Cab&cabSizeId=2&model=Sierra&styleId=SLT&subModelId=31&year=2005&modelId=013&pvc=655&driveTypeId=11&&vehicleModel=/images/gmbp/48012/vehicle/2005/med/31_926L.gif&exteriorColorId=59U&interiorColorId=692&colorOptions=59U^692&exteriorColor=Silver%20Birch%20Metallic%20&interiorColor=Dark%20Pewter%20Ultrasoft%20Leather% 20Seat%20Inserts%20&colorVisited=true&inValidOptions=&brand=sierra&commercial=&originatingBrand=sierra&iPi=2&fPi=3

Bergeros,

Sorry i didn't answer your question about the clifford remote start. I LOVE IT. However, if you want the best equipment be prepared to dish out the coin. Clifford (by D.E.I.) is the best on the market. It has a built in sensor that connects to you coil light, when the light goes out the truck starts to crank. The window roll down/vent/up is a great standard feature. Pretty trick. Thank God my best friend is an installer. took him two days. geeeez i felt bad for him, but not for to long.

XR Freak, thanks for the info. I will certainly post when ready for the additions to the truck. Everyone on this site has been incredibly knowledgeable. If nothing else I am getting smarter and smarter by the post!! ):h Now if I could only remember it all.... Thanks again, I'll add to my wish list.