Big Dave

My HVAC blower stopped yesterday, but the blower for the front windscreen defogger/defroster still works with the HVAC on the far-right setting. The blower stops on any other setting. Are they the same blowers? Just curious if I need to check the relay/fuse or start planning on a bigger repair.

Alan

They are one and the same. That it still works in DEF mode suggests you have the all too common resistor pack failure.

Read up on many other posts on resistor pack replacement.

Alan

69gaugeman

+1

I may have a used one around here somewhere.

Big Dave

Thanks...did the search and found this thread:LINK

My blower works only on the defrost position (no operation at all on any blower speeds when not in defrost mode) so I'm hoping it's just the relay. I'll swap 'em out this evening.

Anyone know if this is a common relay that can be found at a store carrying import parts?

dr bob

Dave--

It's not a relay, it's a resistor pack that lives in the air duct downsteam of the motor, accessible under the hood.

There's also a chance that the wiring for the blower on the side of the HVAC controller was disturbed. Done any work in the dash/console lately? Otherwise, a bit of meter testing under the hood is in order. There are some good threads describing that so no need to retype it all.

My Big Suggestion on changing th resistor is to be sure to put a towel under the duct, so wehn you drop the screw that holds the resistor in place, it sits in the towel and not in the Big Black Hole below. Go head, ask why I recommend the towel. I dare ya!

Lizard928

LOL Dr Bob,

I have pulled these on a few cars and have found one that is dead yet.

I did have that same issue with mine and it was a problem where power wasnt getting to a portion of it, I cleaned the connectors and it has been fine since.

Big Dave

Maybe I'm missing something, but why do you think it's the resistor pack when Randy cured the 100% same symptoms with a new relay (specifically, by swapping for the horn relay)? Just like Randy, it only works on defrost mode....nothing on settings 0-4.

I haven't disturbed the wiring in the dash...ever. I put a new radio in the center console about 4 months ago. *shrug*

Alan

Dave - yes if your switch does not activate the blower even on position 4 then its likely the fresh air blower relay.

It should probably really be called the HVAC relay since it switches more than just the blower.

Its a standard Bosch type SPST (SPDT types will also work fine).

Alan

Big Dave

So would a standard 40 amp 4 pin relay be fine? I don't know much about relays. Maybe I can pick one up on the way home from the local auto parts store....I know...I know....I'm being naive.

AO

Dave, if it's the same as the Horn relay, I've got one you can have. Maybe you can swing by beofre you go home tonight. You can take the engine stand with you too!

Imo000

Rod,

If you can't find it or you don't have one, I have one. Pulled it when the heater core was sold.

IcemanG17

Yup classic blown resistor pack symptom...you can tell by the busted coil or two on the board

Alan

Brian - probably not this time... which is good for Dave because a relay is both far easier to change and far cheaper!

Dave - yes any Bosch style 4 pin (SPST) relay will be fine - the 40A versions are much better than 20A or 30A versions for this - just typically better quality due to the better contacts...

Real Bosch (or Tyco now) relays are better quality than no brand versions...

Alan

Big Dave

UPDATE:

I replaced the relay with a new one and the blower worked at all speeds. Relay was an off-the-shelf version (Heffnauer brand or something like that).

HOWEVER, I stopped on the way home to use an ATM (5 minutes after installing the new relay) and when I started the car again, the blower stopped working. Same symptoms as before...no operating at settings 0-4, but normal blower when set on "defrost".

So, did I get a bum relay or do I have other issues to track down?

Lizard928

possibly a bum relay. If that cured it the first time, try to reseat it first though.