Climate control fan speed

nut11 · 05-10-2004, 09:00 AM

I own a 1998 328is with 90 K miles in perfect mechanical condition. I think the motor is just breaking in, seriously. Unfortunatelly, I'm having problems with the climate control system. Irregular fan speed control. Press a fan speed level and a few minutes later it goes on full blast! Have to turn it off to control the thing. Impulsively, I bought a new climate control DME, installed it, and the problem continues. I get to eat the $280 dealer part cost. Any advise as to an alternate fix? Maybe a fan control module or something? Plus, I have a perfectly good spare DME for the winning assistance. Thanks for any help.

supertack · supertack's Garage

This may sound stupid, but I kinda had a hard time figuring out my defroster when I first got my 328is. I couldn't understand why when ever I pressed the defroster button, the fan speed would go to full blast. Then a board member said, just use the air up button at regular fan speed & that would defrost the windows. Done deal, & good advice. Now in your case, it almost sounds like it has something to do with the actual temp settings. It's as though the interior temp sensor doesn't like what it's getting in relation to the prescribed temp your asking it to maintain, & it's over compensating for the discrepancy. What's bizarre is, I believe the interior temp sensor is on the front of the climate control unit (little round grate), & if you've replaced that, it makes no frickin sense. Maybe someone else has had this happen, good luck.

nut11 · 05-10-2004, 12:30 PM

I've been sleuthing and obtained some advise regarding the resistor on the fan motor as being the potential problem. Apparently, it's a clip on devise located right above the gas pedal next to the heater box. Keep your fingers crossed as I'll check it out asap and I'll keep you posted. Thx for your reply. BTW, my baby is also blk on blk with a spoiler which at first (just bought the vechile) I did not like but it's starting to look good - different anyway. Thx again.

tshegos · 05-13-2004, 02:43 PM

I’m real curious to find out if your idea works. I have a 96 318ic with a similar problem. The defroster blasts on high when used. The AC is really weird – It’s been in the 80s in Michigan this week and when the temp is set to 65 the blower turns on for about 3 seconds and then stops. (The good news in the air is ice cold). In about 4 minutes the blower will blow for a couple of seconds.

Also, the same thing happens when I use the air up, middle or down. It pretty frustrating when it’s 85 and 100% humidity… (too hot for the drop top)

nut11 · 05-19-2004, 01:42 PM

Thx, Tshegos for your patience but it appears it was the resistor for the fan motor. If you have the digital climate control system (no dials), the resistor unit is located right next to the top of the clutch pedal where it slides into a duct with two allen type screws. You can ID it by a five wire snap on connection which is mounted to an epoxy looking glaze which holds the male connection in place and seals the top of the unit. Once you disconnect the connector and pull the unit out, you will see a bunch of 4 inch tines connected to the head which are heat sinks. Looks really wierd but it's neat. The whole unit is roughly 5 by 2 by 2 inches. The BMW part # is 64.11.6.929.540. I don't have a camera, sorry. You'll see it once you pull out the under dash shrouding and do the crawl/contortion factor. Change out took roughly an hour. Hope this helps.

98 328is

kenikh · 10:01 AM

Quote:

Originally posted by nut11
Apparently, it's a clip on devise located right above the gas pedal next to the heater box.

I have a '99 E36 and the clip in unit doesn't appear to fit my car. I posted a thread trying to solve this issue:

Blower resistor issues in 323iS; did BMW change resistors for one year?

It appears you are talking about the aluminum screw-in unit I was referring to. Are this and the plastic clip in unit two different pieces, with two different locations? If so, where does the plastic clip in unit go? By the clutch pedal? I can't see it. I am so preplexed...

nut11 · 06-10-2005, 07:53 AM

Sorry it took me so long to get back. I just don't know. Call your dealer and a service tech will tell you. Good luck.