Clickity Clack w/out diesel fumes. Help!

[DieSly]

I don't know how to search for a remedy to my newest problem so forgive me if this has been slathered about somewhere already. Anyway, I shut off my truck ('94) last night and this strange steady clicking sound started up near the heater blower motor. It seems to be coming from within the cab. It lasted about 45 seconds I guess and then stopped. The few following times I shut off the truck it did the same thing. This morning it even started up as soon as I turned the ignition to get the glow plugs warm and it continued for about the same duration. I have no idea what could be going on... does anyone have an idea what might be happening? Odd.

[joed]

See this thread about my coworker's truck.


[URL="http://www.thedieselpageforums.com/tdpforum/showthread.php?t=33123"]

Joe.

[DieSly]

Thanks Joe! My '94's issue sounds identical to what was going on with the other '94's... I'll have to scope it out!

[Robyn]

The noise is coming from the servo motor that controls the AC vent for inside only or outside air.

The little devil is down under and behind the AC box between there and the firewall.

The little motor is a bitch to get to but you can worry the electrical plug off and the thing will stop making noise.

The motor is designed so it either opens or closes the recirc flap and once the flap is to its stop either way the motor exceeds the allowable amp draw and it shuts off.
The gears in the little gear box are plastic and wear to the point that they start skipping and the thing will just keep running as it does not load the motor enough to trigger the shut down. (DUNK DUNK DUNK DUNK DUNK DUNK DUNK it goes)

My 94 did this about two years ago. Summer I plug the wires in and run the recirc shut so the AC works best and for winter I open the sucker. I just leave the wire unplugged.

Getting the little motor out is a real nasty job with the HVAC unit in the rig

Another wonderful design.

Missy