Heater Controls 87 300E
 

I have difficulty getting heat using my climate control mechanism.

The best way for me to get heat is to push the button for the defrosters. The other buttons activate only the fan and not the heater. I can hear clicking sounds when I turn the temperature control knob and when I push any of the control buttons.

After the car has been running for about a half hour all the buttons seem to work in that the heater seems to respond as it is supposed to.

Any idea what I might trouble shoot in order to correct the problem?

Thanks.

PS I did a couple of searches but there are evidently different systems for various car series. Any information on the 1987 300E will be helpful.

1. First turn the car on but don’t start it. If you push the any of the buttons does it change the air flow or just blow out of all vents? If not then I think your system is in malfunctioning mode it goes into an override function.
2. Does the fan seem to go on and off intermittently? It’s actually not, it is timed in seconds.
3. Just count the seconds or use a stop watch, after one clicking noise from the relay the fan will go on for XX seconds pause for four then on another same XX seconds and so on. The number of XX seconds should be the same and not intermittently, this number should also tell you what is wrong with your system.

Thai GI sends...

Thanks Thai,

Thay is valuable information. Will check it out in the morning.

:)

That cant be right. The vents are controled by vacuum. If the engine is not running then the vents will not operate.

Dave,

You’re right I’m only thinking electrically and not pneumatically. OK everything is the same except turn the car on, have the engine running the vacuum from the intake manifold supplies the power to operate the vents. :p


Thai GI sends...

Earl, two things come to mind, the aux water pump and the monovalve. BTW, you stated you got normal function after about 1/2 hr. :confused: thermostat stuck open :confused: . Also when you hit the defrost mode before the car is warmed up, what do you get??