Busted Mix Door Control Unit?

[Damicci]

1994 Q45 200k+ MilesDid the Heater post fix earlier this year.

Now it seems the control unit is not functioning.Took the HVAC and Radio out and adjust temps from 65-85 and the unit doesn't move. so removed the unitthis:zer...5.JPG

And touched the top left most pin and the bottom most pin to 12v power and the motor moved. But when I connect it back to the HVAC unit. it moves into a default? position and then no longer responds.

Any idea? I haven't been able to find anything on this issue in particular. just the heater mix door post issues.

[Damicci]

So I tested the unit again and it moves but very slightly as if it is lacking power. I guess I can do a voltage test to make sure it's getting proper voltage or the unit needs to be replaced.

[Q45tech]

The main reason you don't take short cuts in jury rigging old door is the totally disassemble the system and clean the accumulated dirt, filth, and grim and replace the entire door along with anything else you see iffy.

[Damicci]

Thanks and I did clean the area and regrease the tracks at the time of repair. the door post is fine. The issue is the unit pictured.

Now could you be so kind as to tell me what the unit is called so I can try to locate a replacement.

[Q451990]

Did you run the self test in the FSM? That should tell you which motor or sensor is bad...

Heath

[Damicci]

Haven't had a chance to so will do it this weekend when I am free, but I am pretty sure the part displayed is done and needs to be replaced.

[Q451990]

Haven't had a chance to so will do it this weekend when I am free, but I am pretty sure the part displayed is done and needs to be replaced.

Very possible. If you have anything like http://www.pullapart.com in your area you can probably pick one up dirt cheap. I would feel comfortable trying a used part here, since I have never heard of a failure in the past. You have a good chance of getting a good one...

Heath

[Damicci]

That's what I was thinking, was going to poke around ebaymotors also. Thanks for the advice.

[Damicci]

replaced the unit and regreased the sliders for the mix doors and all is well. It still seems to not move as smooth but moves alot better when getting power from a running alt instead of the battery.