A/C blower problem... please help

Lucky · 05-20-2002, 07:05 AM

I charged up the AC over the weekend getting ready for the summer heat. Blows nice and cold! But, I have a new problem with the system -- the circulation fan only runs when set to high and doesn't run at all when set to either of the two lower speeds. No problem if you don't mind the sound of a 747 taking off and excessive airspeed within the cabin!

I haven't cracked open the Bentley or Haynes manuals yet, so I don't have a plan on how to isolate the cause. I'm hoping someone else has had this problem before and can help me quickly pinpoint the cause. What are the likely causes, and where should I start?

-- John

ps - I was cleaning the door pockets over the weekend and found the Koni adjustment knob (hidden in there by the PO)... checked the front struts and found they were set as firm as possible... dialed back one turn and when for a drive... what a difference!! Car rides great and seems to turn in better with the front softened up slightly!

jlex · jlex's Garage

Sounds like a bad switch to me. Look at bentley & take some readings with your digital meter. If you have the books, I think there's something in there on that.
regards,
jlex.

Sean Hamilton · Sean Hamilton's Garage

Gee, I didn't know that I could adjust my koni's *on the car*.
I saw them go in and the mechanic adjusted them prior to installation.
So, there ya go. I might check mine out now

John, the consol fan switch dial may be the culprit - whip it out and check for contact at the lower settings.

Lucky · 05-20-2002, 11:44 AM

I'll start with the switch then. I was hoping it would just be a fuse or two that needed replacing. No such luck.

Sean, I have the Koni adjustables front and rear. Only the fronts can be adjusted on the car. If your struts are adjustable, there will be a small, flat-ended piece of metal sticking out of the top bolt. The adjustment knob slips on top of this. The knob has an arrow which tells you which way to turn for firmer (or softer) settings -- I can't remember off-hand which is which, if you don't have the know pliers should work fine. I plan on trying a few more settings to find the ideal for my driving style -- minus 1 turn (from firmest) feels really nice at the moment!

schulr · schulr's Garage

had a similar problem with my ac, 87 carrera, and if you lift up the capeting on the drivers side, there is a hole in the wall with what looks to be a sencing device with a four prong plug. Mine was removed. when I pluged this in, the fan worked on all speeds. Also recharged the system up to 35 pounds with r 134 and the results are very cool, not great, but much better.

Bob

Lucky · 05-20-2002, 03:40 PM

I had the shifter out a couple of weeks ago to replace the bushing in the tunnel. I may have knocked a connector loose. Thanks for the excellent tip.

On the subject of R134a. Mine has been converted and seems to work well. One suprise is the amount of R134a I've had to put in for the changeover from R12. Factory fill was 39oz of R12 and from what I've found, you need less R134a... around 85% of what you would use with R12. I've put in 48oz of R134a and my low side pressure is still a bit low (around 25 to 30 psi). I'm afraid to add more, so I'll see how well this works before I do so.

Has anyone else had to add as much R134a?

Lucky · 05-22-2002, 02:22 PM

Turns out I had knocked the plug off the big-ass resistor (this is the spring-like thing hidden behind the floorboard in the passenger footwell) when I had the shifter out for bushing refurbishment.

So if you find your AC blower only runs on the high setting, then this is the likely cause.

Thanks to those that suggested troubleshooting ideas.

-- John