AC Controls

my 98 gp has the digital dual climate thermostat for the AC controls (not the one with the dials, but the buttions and the display instead) and its reading the temp in celsius, i wanted to know how to get it back to reading fahrenheit, i had the AC repaired and after i got it fixed it went into celsius mode, i dont know what they did to it, could someone maybe check their service manual or something and see if theres a way to set this back to fahrenheit? thanks!

I looked could not find anything sorry

k, thank you for looking anyways

I'm assuming since you have the digital dual climate HVAC controls you have the Driver Information Center (DIC). On most GM cars that have DIC you set whether you want the readout in English or Metric (E/M) at the DIC.




http://i5.photobucket.com/albums/y186/lizzywiz/gtp.jpg
Thrasher CAI, DHP v1.0 PCM,
3.25 SC pulley, CAIT GMAF, Hi-Flow CAT,
u-bend delete, 160 TS, ZZP Stage 1 TB,
TB spacer, MSD 8.5mm wires, Autolite 104s,
Goodyear Gatorback Serp. & SC Belt,
Nitto NT555R Drag Radials

i think i might have DIC, how would i know? and where would it be

i think i might have DIC, how would i know? and where would it be

It should be located to the right of the steering wheel in the center of the dash above the center AC vents and center console. It has 3 buttons and a digital display. The buttons are marked ENG/MET, RESET and MODE.

If you have a DIC the button you press is the ENG/MET and it will change the temperature to farenheit.




http://i5.photobucket.com/albums/y186/lizzywiz/gtp.jpg
Thrasher CAI, DHP v1.0 PCM,
3.25 SC pulley, CAIT GMAF, Hi-Flow CAT,
u-bend delete, 160 TS, ZZP Stage 1 TB,
TB spacer, MSD 8.5mm wires, Autolite 104s,
Goodyear Gatorback Serp. & SC Belt,
Nitto NT555R Drag Radials

oh ok yea i got DIC but it diddnt change it back to fahrenheight, i held it down for a few seconds, and nothing, would there be any online instruction manual about the thermostat ac control?

if i took out the ac control deck from the dash, would anyone know if there might be a switch somewhere on it to change the temp readout?

sorry if i seem like such a pain in the a** about this, but its been irritating me so much. if anyone has any suggestions or site links about this please let me know. thank you!!!

I have the same control in my 99, and the DIC is not connected to the A/C controls. I checked my owners manual, and it doesn't say how to change from C to F, so i tried every button combo I could think of and it wouldn't change. Are you sure they didn't replace your unit with one calibrated in Celcius by mistake?

yea im pretty sure, i dont think my mechanic would have one just sittin around his shop, ill have to ask him about it. it was in fahrenheight when i bought the car. if i have to then i may just end up getting another one from ebay or something, hoping that one is in fahrenheight.

I'll keep digging for you, and see if it's changeable. I'll let you know how to do it if I find it.

I didn't know GM had two different digital AC head units for the Grand Prix. Ive only seen one GM part number. What makes it switch between English or Metric is a simple ground which originates at the passenger side fuse block area. The Grand Prix's AC/Heater control relative to setting the display in fahrenheit or celsius is not as sophisticated as other its GM counterparts.

Anyways, here's his problem. There are 2 main connectors at the back of the HVAC control unit. C and D. At connector D there is pin D7. This is the English/Metric connection point. If this point is grounded it reads Metric-Celsius. If this is open (no ground) it reads English-fahrenheit. The ground originates from ground number G201. BTW - The specific wire you will be looking for is black.

Based on Richtazzes theory that you got a head unit wired in Celsius, then someone screwed up by putting a ground in the AC/Heater control panel and not in the wiring from the connector plug and back but its a possibility.

If you're handy with a multimeter, set it to ohms - resistance. Check at connector D, pin D7 relative to ground. If it reads a short then its set for Metric. All you'll need to do is open the wire at this point to read fahrenheit. And if I have time I can send you the 97 - 98 GP wiring diagram but I don't know your competency level in DIY and electrical problems. Good luck!




http://i5.photobucket.com/albums/y186/lizzywiz/gtp.jpg
Thrasher CAI, DHP v1.0 PCM,
3.25 SC pulley, CAIT GMAF, Hi-Flow CAT,
u-bend delete, 160 TS, ZZP Stage 1 TB,
TB spacer, MSD 8.5mm wires, Autolite 104s,
Goodyear Gatorback Serp. & SC Belt,
Nitto NT555R Drag Radials

Before you start re-wiring your unit, you might want to try holding the driver and passenger buttons down at the same time while the fans are off...The readout on your screen should change to "00" and then your driver-side dial should allow you to switch from farenheit to celsius. :smile:

Before you start re-wiring your unit, you might want to try holding the driver and passenger buttons down at the same time while the fans are off...The readout on your screen should change to "00" and then your driver-side dial should allow you to switch from farenheit to celsius. :smile:
ive tried that and it DID readout the "00" but when i turned the dial the numbers would just change from numbers 00 through 22 and if i moved the passenger dial it would change to just a random number, like 173 or 11 and still stay in celsius. Is there another way to do that maybe? if not then ill take out the ac head unit and check the ground points, that sounds like it may be the problem, if you do have an electrical readout that you can send that would be helpful. ill let everyone know how it goes. thanks again everyone for all this help!! :)

ive tried that and it DID readout the "00" but when i turned the dial the numbers would just change from numbers 00 through 22 and if i moved the passenger dial it would change to just a random number, like 173 or 11 and still stay in celsius. Is there another way to do that maybe? if not then ill take out the ac head unit and check the ground points, that sounds like it may be the problem, if you do have an electrical readout that you can send that would be helpful. ill let everyone know how it goes. thanks again everyone for all this help!! :)


Mike561 - Click on the link below and please verify that's your HVAC head unit. Also since you had the unit out, can you verify the Delco part number on the paper data tag. Should be part number 09351482. This climate control should be similar for all Grand Prixs 1998 - 2000. For 2001 and up it changed to include the part number.

Maybe the guy with the 2003 Grand Prix will be kind enough to show you which buttons or controls he's talking about from the link/pic.

I'll convert my PDF file wiring diagram to JPEG and post it later.


http://images.mainstreetcommerce.com/3.9/media/item_image_sheet.aspx?domain=lkqcorp.com&auction_guid=ce152abb-142e-4e10-a26d-16455677e89c



http://i5.photobucket.com/albums/y186/lizzywiz/gtp.jpg
Thrasher CAI, DHP v1.0 PCM,
3.25 SC pulley, CAIT GMAF, Hi-Flow CAT,
u-bend delete, 160 TS, ZZP Stage 1 TB,
TB spacer, MSD 8.5mm wires, Autolite 104s,
Goodyear Gatorback Serp. & SC Belt,
Nitto NT555R Drag Radials

yea thats exactly what my ac head unit looks like. the number on it is 16266022 where would the HVAC unit and the wires that i need to look for be?

yea thats exactly what my ac head unit looks like. the number on it is 16266022 where would the HVAC unit and the wires that i need to look for be?

Ok....we're getting somewhere. On the part number I'm assuming its correct but not 100% sure. There are other variations of the auto climate control unit to include part number for models years 97 - 00. Maybe our friendly ASE certified parts man Richtazz can weigh in. I found one for a GTP and it was 9355222. :dunno:

The wires are with the connector plug that plugs into the auto climate control unit. I call it the HVAC head unit but I'm referring to the same thing. I sent a JPEG image wiring diagram but you'll have to zoom in to see the area. The AC Heater control is the block diagram to the upper left of the page. In the same area of the page the output/inputs are shown to include pin D7 and the grounding and English/Metric legend.
Its the area where the arrows are pointing to.

Good luck and let us know if you need further help.




http://i5.photobucket.com/albums/y186/lizzywiz/gtp.jpg
Thrasher CAI, DHP v1.0 PCM,
3.25 SC pulley, CAIT GMAF, Hi-Flow CAT,
u-bend delete, 160 TS, ZZP Stage 1 TB,
TB spacer, MSD 8.5mm wires, Autolite 104s,
Goodyear Gatorback Serp. & SC Belt,
Nitto NT555R Drag Radials

ah ok i got it, its in fahrenheight now, had to study the diagram for a bit but i figured it out, wierd that it was just a small little wire that had to be disconnected. thanks to everyone your help, i really appreciate it! :)

ah ok i got it, its in fahrenheight now, had to study the diagram for a bit but i figured it out, wierd that it was just a small little wire that had to be disconnected. thanks to everyone your help, i really appreciate it! :)

Congratulations Mike562. :bigthumb: We're here to help one another and you're welcome. Good luck and I hope you figure out the other problems you're having. Welcome to the DIY club. :lol2:




http://i5.photobucket.com/albums/y186/lizzywiz/gtp.jpg
Thrasher CAI, DHP v1.0 PCM,
3.25 SC pulley, CAIT GMAF, Hi-Flow CAT,
u-bend delete, 160 TS, ZZP Stage 1 TB,
TB spacer, MSD 8.5mm wires, Autolite 104s,
Goodyear Gatorback Serp. & SC Belt,
Nitto NT555R Drag Radials

Congratulations Mike562. :bigthumb: We're here to help one another and you're welcome. Good luck and I hope you figure out the other problems you're having. Welcome to the DIY club. :lol2:




http://i5.photobucket.com/albums/y186/lizzywiz/gtp.jpg
Thrasher CAI, DHP v1.0 PCM,
3.25 SC pulley, CAIT GMAF, Hi-Flow CAT,
u-bend delete, 160 TS, ZZP Stage 1 TB,
TB spacer, MSD 8.5mm wires, Autolite 104s,
Goodyear Gatorback Serp. & SC Belt,
Nitto NT555R Drag Radials


Show off. :lol2:

glad you figured it out, I was about to take mine out and look, as I could find no info on it.

my 98 gp has the digital dual climate thermostat for the AC controls (not the one with the dials, but the buttions and the display instead) and its reading the temp in celsius, i wanted to know how to get it back to reading fahrenheit, i had the AC repaired and after i got it fixed it went into celsius mode, i dont know what they did to it, could someone maybe check their service manual or something and see if theres a way to set this back to fahrenheit? thanks!
I have the same problem and have pushed every button in every combination I could think of I even tried disconnecting the battery and letting it sit and nothing works. The mechanic who worked on it has no idea how it changed. I to will be watching the posts in hopes of a resolution! God luck to both of us.

I have the same problem and have pushed every button in every combination I could think of I even tried disconnecting the battery and letting it sit and nothing works. The mechanic who worked on it has no idea how it changed. I to will be watching the posts in hopes of a resolution! God luck to both of us.
Based on info. gathered in this forum I took my unit out and disconnected a seperate black wire and that was it. I just want to say thanks to all who contributed.

Based on info. gathered in this forum I took my unit out and disconnected a seperate black wire and that was it. I just want to say thanks to all who contributed.

Wow! Two for the price of one. Glad you got yours resolved too.:bigthumb:



http://i5.photobucket.com/albums/y186/lizzywiz/gtp.jpg
Thrasher CAI, DHP v1.0 PCM,
3.25 SC pulley, CAIT GMAF, Hi-Flow CAT,
u-bend delete, 160 TS, ZZP Stage 1 TB,
TB spacer, MSD 8.5mm wires, Autolite 104s,
Goodyear Gatorback Serp. & SC Belt,
Nitto NT555R Drag Radials

yea it was just a little black wire, i love finding easy fixes like that :)