'97 Grand Prix GT Help Heater problem

helicopter23 · #1 01-28-2007, 08:42 PM

I have a 1997 Pontiac Grand Prix GT with 90k. About a week ago my car heater started acting up. The heat comes out warm instead of hot and the heater only works on the highest level (5). What's going on with the heater and is it an easy fix or will I have to take it somewhere, how much will parts and labor cost? By the way the heated seat seems to work fine and the rear window is fine. Thanks for the help.

helicopter23 · #2 01-28-2007, 10:05 PM

I read that it could be the HVAC fuse is blown because that controls levels 1-4, could that be correct? Where is the fuse box located on the '97 Pontiac Grand Prix?

BNaylor · #3 01-28-2007, 11:58 PM

Two fuses that could affect it are the HVAC CTRL and HVAC HI locatd in the fuse box by the glovebox. Since the blower works in position 5 the HVAC HI fuse is good.

If the fuses check good then most likely you have a bad blower motor resistor (BMR) or blower motor control module. Manual HVAC uses the BMR and auto climate control (ACC) uses the module.

As far as for low heat check the thermostat.

helicopter23 · #4 01-29-2007, 12:02 AM

Thanks,

I know very little about cars, were can I check the thermostat? I will check those two fuses you mentioned tomorrow and get back to you, much appreciated.

BNaylor · #5 01-29-2007, 12:11 AM

You're welcome. The link below located at our Tips & Maintenance subforum will show the location of the thermostat and how to replace it. Sounds like yours is stuck partially open or not regulating at the stock 195 degree mark. Good luck.

Click here

helicopter23 · #6 01-29-2007, 12:22 AM

Also the warm air is coming only out of the middle consoles the far left end and right end consoles has nothing.

BNaylor · #7 01-29-2007, 12:34 AM

I'd start with checking the HVAC CNTRL fuse and also make sure there is 12 volts at the fuse socket even though the fuse may look good. The vents are controlled by a combination of electrical signals from the climate control unit and engine vacuum. There are various actuators used to control the HVAC system vents and temperature. The engine vacuum source is the Y fitting at the rear of the upper intake manifold and routes along the firewall, then by the battery and into the main wiring harness that runs into the firewall.

helicopter23 · #8 01-29-2007, 01:36 PM

I checked both fuses and their fine, I never checked the HVAC CNTRL fuse for 12 Volts. When the settings are on 1-4 it doesn't even sound like anything "turned over".

BNaylor · #9 01-29-2007, 01:59 PM

I would say you may have more than more problem with your HVAC system. However, the missing blower speeds 1-4 is typically a bad blower motor resistor providing that you have a manual not digital - ACC.

wlkjr · #10 01-31-2007, 07:21 PM

could it possibly be low on coolant?

Rottweiler28 · #11 02-06-2007, 04:07 PM

Quote:

Originally Posted by wlkjr

could it possibly be low on coolant?

I could see the low coolant causing heat loss but can't see it affecting the blower. BTW you can test the thermostat by boiling it in a pot of water, this will tell you if it is opening, then take it out if it opens ( I used a fork..lol) then as it cools you should see it closing. I even went a step further, you can buy a thermometer to tell you exactly what temperature it opened at. I used one which is used to cook some kind of hard candy or something, dunno it was a gift as I was asking everyone if they had the type you stick in a turkey..lol, well this one worked like a charm and showed my thermo opening between 88 and 93 degrees Celcius. Its supposed to open at 91, not bad in my opinion, cool little gadget

BNaylor · #12 02-06-2007, 04:53 PM

One symptom that I've seen on SII 3800 engine when the coolant is actually low in the radiator and reservoir is you will get that classic gargling sound in the cabin area of the HVAC where the heater core is located. Like when you gargle with mouthwash. Coolant is constantly flowing through the heater core whether you have heat on or not.

helicopter23 · #13 02-07-2007, 02:12 AM

"One symptom that I've seen on SII 3800 engine when the coolant is actually low in the radiator and reservoir is you will get that classic gargling sound in the cabin area of the HVAC where the heater core is located. Like when you gargle with mouthwash. Coolant is constantly flowing through the heater core whether you have heat on or not."

bnaylor-
I have that same sound although I would say it is more of a "swooshing sound" like fluid is moving back and forth.

Should I check the coolant? Or what should I do? It's been making this noise for about 1 year now.

BNaylor · #14 02-07-2007, 02:32 AM

Quote:

Originally Posted by helicopter23

bnaylor-
I have that same sound although I would say it is more of a "swooshing sound" like fluid is moving back and forth.

Should I check the coolant? Or what should I do? It's been making this noise for about 1 year now.

As for your low heat problem absolutely. Be sure to check the level in the radiator first and then the reservoir. As to the blower speed control problem that sounds like another issue.

helicopter23 · #15 02-07-2007, 02:34 AM

I Agree I think its the blower motor resistor because levels 1-4 on the blower are "dead". If I took this to a GM dealer how much would a new blower motor resistor cost to replace with labor?

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