Rich W

Long ago, in a thread far, far away I started working on some HVAC issues.

The background: in 2002, everything was working fine. The valves worked, the fans worked, the rear blower fan worked, all in joy and harmony (OK, the A/C didn't work but that was because the evaporator coils had a hole in them).

However, in late 2002/early 2003 the car sat idle, outdoors during a wet East Coast winter. Temperatures weren't particularly cold, but nevertheless low. Condensation formed in the trunk/boot.

Spring 2003 - car is finally ready to be driven. Some electrical gremlins force dehumidification of the trunk. Solves the main problem (speedo). HVAC works somewhat oddly - when fan speed is raised on the CCU, more air comes out the left than the right dash vents, but nevertheless is barely blowing. When defrost is selected, more air blows out the right defrost vent than the left (which makes for really fun driving).

Fall 2004 - replaced the A/C evaporator coils (a job for the patient, to be certain since it took almost 15 hours of work over two days to complete). Fans still have same issue - barely blowing air, but markedly more out of one side than the other.

I'm at the point where I'm ready to start tackling this again. If it was just one fan all the time, then I wouldn't be so concerned. I'd simply replace that blower fan. But that fact that the air flow apparently switches sides leads me to believe there is another, larger issue. BTW, I got the same results when I swapped out the CCU. I'm starting to suspect the control board on the firewall, but would like to run some basic checks on it before pulling it out of the car.

Any suggestions/procedures on how to narrow down the problem to the correct culprits?

Rich

Smokin

You might try searching under "servo problems"... Seems I've heard stories like this before...

Rich W

I've verified the servos are working correctly. Should have put that in the original post.

Rich W

Update:

After checking the voltages coming from the CCU were correct, and checking the voltages from the firewall mounted conditioner to the fans were correct, I decided to pull the fan housings.

After opening the passenger side fan case, I did a quick spin by hand. The fan did not complete one revolution. I then energized the fan via the CCU, and it failed to turn. The driver side fan was blowing strong. So, despite the somewhat contradictory indications, the passenger side fan is the culprit in this issue. Thankfully it is the easier one to get at, although I'll pull and inspect the other fan as well.

frankvan

Somewhat similar situation with my hvac system. The fans are both blowing and I get fairly equal air out each side of defrost. The problem is that although the fans are making lots of noise I seem to be getting hardly any air blowing out any of the vents, esp. noticable on the defrost (and yes I know which slider controls what,etc... ).
All servos are working.
disconnected heater pipe under dash (from heat exchangers) and the fans are definitely sucking more than they are blowing.

Question - could there be something blocking the fan output (leaves, dead mice?) and is there a way to access that area of the plenum to clean it out?

The other thing I was thinking it could be is an obstruction in the heat supply tubes - maybe the flapper valves in the rear wells - any way to check that they are functionig properly?

I'm not sure if part of it has to do with the -20 weather lately.