My '86 series III had to sit for a few months unused unfortunately. When I finally went out to get her going again, I didn't have too much difficulty and started driving around the neighborhood to make sure everything was ok. In general all was good, except the HVAC would not switch which ducts the air came out of. No matter what temp I set it on the air is hot and never changes vents (mostly side and footwell vents). The fan works fine. Any ideas what I could do to get this working properly again? Before the extended layover it worked fine.

Thanks,

Eric

 

Are you sure the flaps are stuck?

When you adjust the temp control dial do you hear a faint whirring sound? You should. That's the servo motor which *operates* the flaps.

Cheers
DD

 

Hey Doug,

I should have chosen my words more carefully. Rather than stuck, I should say the flaps don't move from their current location. The air never comes out of any other location no matter where I switch the temp control or speed control knobs. Also, I do not hear any whirring sound.

As a side note I did replace my A/C amplifier 4~5 years ago. Doesn't mean it can't go bad again, but the part in there now is not the original part from 1986.

Thanks,

Eric

 

Hi Eric. The amp sends current that rotates the servo. The servo makes the whirring sound Doug mentioned. I would take the "cheek panel" on the right side off and see what is going on. The cheek panel is on the side of the console and the floor vent screws into it. Warm up the car and then do the knob thing like before. That will make it much easier to hear the servo plus you can actually see the flap rods move. If no sound or movement I would check for vacuum and the circuits before worrying too much. Good luck.

 

The system has 4 fuses that you'll need to check....not only to see if they're blown but to check for tight fit in the clips and no corrosion.

Two fuses are in the RH fuse panel below the glove box. One is behind the RH cheek panel, clipped to the side of the heater case, the last one is behind the LH cheek panel on the black ground wire from the amplifier

Cheers
DD

 

Thanks for the pointers! I will check all of that this weekend and report back.

Oh, and yellow series3, by checking circuits, do you mean checking the fuses Doug mentioned or something else? If something else, please let me know what/how to test.

Thanks again!

Eric

 

Eric,

check fuses and operation of servo as confirmed by the whir heard as others have described. If the system worked previously and now does not after storage.. There are 2 items which frequently are problems...the relays inside the amplifier which drive the servo forward / reverse, and the feedback potentiometer on the servo. Since you had the car in storage...i suggest checking the feedback pot. It is not a sealed item and i have seen corrosion develop or broken wires in this pot.

to test you will need a 9 volt battery with leads and a volt meter to check resistance. Go to www.jag-aire.com and download the installation manual from the amplifier product page...it has detailed instructions how to test the feedback pot and the sensing system. If the feedback pot checks out...you likely have a failed amplifier.

Hope this helps...

Cheers

Gary

 

Eric,

check fuses and operation of servo as confirmed by the whir heard as others have described. If the system worked previously and now does not after storage.. There are 2 items which frequently are problems...the relays inside the amplifier which drive the servo forward / reverse, and the feedback potentiometer on the servo. Since you had the car in storage...i suggest checking the feedback pot. It is not a sealed item and i have seen corrosion develop or broken wires in this pot.

to test you will need a 9 volt battery with leads and a volt meter to check resistance. Go to www.jag-aire.com and download the installation manual from the amplifier product page...it has detailed instructions how to test the feedback pot and the sensing system. If the feedback pot checks out...you likely have a failed amplifier.

Hope this helps...

Cheers

Gary