clicking noise

[Diesel 4 blood]

I have a 94 c2500 auto 4x4 there is a clicking noise maby a knocking noise behind the glove box when I turn the key on and when I shut it off lasts about 60sec any body have this happen if so what was it I've checked the relays behind the glove box and its not them :confused:

[sctrailrider]

Mine was the fresh air door motor, it's under the dash passenger side, close to the floor behind the blower ... it's hard to get to to change, I just unplugged the wire going to it...

[Robyn]

The recirculation servo moto has failed.

The little plastic gears in the unit strip then the thing sits and goes click click click.

Without pulling the heater out, you can't get to it.

These servos move the doors in the heater and the recirc door servo moves the door, and when it reaches full motion (open/close) and comes to a stop, there is a sensor in the servo that senses the rise in amperage draw as the servo stalls, and then shuts the thing off.

When the gears wear out, the thing can't reach the amp draw to shut off and then the noise.

The part is not too $$$$$ but the entire dash and heater has to come out to fix it.

Damned poor design IMHO

What ever happened to cable controls ??? they rarely if ever gave up.

Your problem is a common one one these rigs. I have been through 2 of these failures.

During the summer, I set the door to recirc to allow the AC to work at max and in the winter months set he thing to fresh air.

Sort of anoying, but its not catastophic.

There is a little plug on the motor right behind the heater box above the passenger foot area on the underside of the heater next to the firewall.


Good luck

Missy

[Diesel 4 blood]

Thanks for the replies the condenser has a hole in it I'll just in plug it for now then when I fix the ac I'll decide if I want to pull the dash I had to pull the dash in my 82 TA it was not fun :mad::mad:

[DmaxMaverick]

Condenser? The evap core is under the dash, condenser is in front of the radiator. When you do get in there, it's probably a good idea to do a complete refresh, replacing all the servos and cores, unless you really enjoy the R/R.

[Diesel 4 blood]

Its weird one of the cross over tubes on the condenser had a hole rot through it so as fast as I put 134a in it blows right back out