Blower Fan and Head Lamps

I have a '98 Grand Prix GT. Periodically, my HVAC fan will go out all of a sudden and will only work on Level 5 (highest setting). When the fan goes off, my headlamps simultaneously go off as well. The headlamps will go back on when you switch the fan off or onto level 5. (You can actually hear the headlight switch on and off.)
I noticed there is a fuse the controls the low speeds of the blower fan as well as the headlights.
I already replaced the resistor twice so it's not that.

Any help would would be greatly appreciated.

check your owners maual and look for curcuit breakers that may be connected to those same systems

I have exactly the same problem but my car is a GP 1999. I change the blower resistor but the problem still. If any body have an idea please let me know.

It's weird. All of a sudden the blower goes off and the daytime running lights click off (it's a pain at night since you have no headlights until you turn them on manually).
The heated seats, driver's information center, rear defroster, as well as the HVAC and daytime running lamps run on the same electrical system. I can't figure it out. It will work for a while and then turn off without warning.

check all your battery connections and grounds first, as unless you have a bad underdash harness, the systems you are having problems with are unrelated, both in location and fuse circuit.

According to the owner's manual, the electrical systems I mentioned are controlled by the same fuse circuit. So you think it might be a bad harness?

I too am having the same exact problem with my *97 Grand Prix. I have had the resistor changed, fuses and relays checked and nothing worked.
My mechanic has pin pointed the problem to a "small electronic contol box" under the steering column with several wires plugged into it. I can move it and the lights and fan motor will work for a few minutes, but after shutting off the engine, the problem returns. Does anyone know what this module might be, or does this sound familiar?

I too am having the same exact problem with my *97 Grand Prix. I have had the resistor changed, fuses and relays checked and nothing worked.
My mechanic has pin pointed the problem to a "small electronic contol box" under the steering column with several wires plugged into it. I can move it and the lights and fan motor will work for a few minutes, but after shutting off the engine, the problem returns. Does anyone know what this module might be, or does this sound familiar?


The part you are referring to is the ignition switch control module and harness. It is all one piece less the key tumbler.

Here's a pic of it:

http://i5.photobucket.com/albums/y186/lizzywiz/switch_igntion.gif




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 am having the exact same problem, as well.
I have a 2001 GTP and it is behaving just as you describe.
Please help...

I realize that this issue is from last year, but I just had the same issue and was able to fix it myself with a bit of "hillbilly engineering" and wanted to share my solution. My 2000 Grand Prix (SE 3.1 engine, manual HVAC controls) has had numerous electrical issues (power windows stopped working and radio stopped working) and I was able to fix them all by running a jumper in the fusebox from a working circuit to the malfunctioning circuit. For example for this specific issue I made a small metal jumper (flat strip bent to "U" shape and inserted into fuse slot along with fuse) to give power from the "Canister Vent" circuit to the "HVAC Control" circuit, and everything works fine. I tried to add a picture but I don't think it worked. Feel free to e-mail me at bretcomstock@comcast.net if anyone has questions. Hope this helps someone else. I just can't imagine what a dealer would charge to fix their crappy design/quality.
http://www.automotiveforums.com/vbulletin/C:\Documents and Settings\HP_Owner\My Documents\My Pictures\Kodak Pictures\2006-08-15\100_1049.jpg

In an earlier post Bnaylor mentioned that the time to fix the ignition switch control module and harness was 1 1/2 hours. Is this an estimate for the "experienced" mechanic or an average joe that has the right tools?

resurecting and old thread is a bad idea. The moderators frown on it, and it makes things hard to track. Please start a new thread on this issue. I'm sure when they see it, they will close this one.

resurecting and old thread is a bad idea. The moderators frown on it, and it makes things hard to track. Please start a new thread on this issue. I'm sure when they see it, they will close this one.

Somehow we missed this one Rich. The thread was resurrected by the previous poster bcomstock. On bringing up old threads AF rules are fairly clear. We prefer that it not be done. The best thing to do is make a new post which normally gives better visibility and response.

As to the question asked, the 1.5 hours is what it took me. Time to repair will vary depending on whether you are an inexperienced or experienced DIY person or even auto tech. The Mitchell's guides allocate 1.9 man hours to replace the ignition switch and harness and that is for Pros. One factor is to have all your supplies and proper tools on hand ready to go.

In the meantime rules are rules. Thread closed.