I get no response from any of the functions/buttons on the climate control unit. Did a search, didn't reveal anything. 1987 E300TDT, only 237,000 miles (you'd think these components would last!) Is there a way to check the unit before I purchase a new/rebuilt/used unit to verify the problem? Thanks.

 

I bit the bullet and got a rebuilt unit from George Murphy.
You can check fuses, etc. and check the aux coolant pump for being stuck.
I will check Alldata for a test procedure.

 

Is it just the blower doesn't come on for any function, or nothing at all happens? Often the blower coming on is the only noticible indication the control system is responding; you may have a bad blower motor or blower control.

 

Nothing happens, no defrost, vent directtion change, A/C, fan speed, nothing.

 

you better bit the bullet too.

seems the AC pushbutton module gone kaputz.

 

I agree; this can be caused by a bad (stuck) auxiliary coolant pump which draws too much current and fries the circuits in the control.