climate control question

[larry perkins]

hey forum, i know i have seen a description some where,but do you know what would cause the fresh air/recirculate red light to blink(the light that normally tells you that you have the recirculate function is activated)
thanks
larry perkins

[larry perkins]

sorry i went brain dead,its a 1989 300te
larry perkins

[stevebfl]

The light blinks when the system is placed in the diagnostic mode. In places I have seen this the diagnostic lead was grounded.

[larry perkins]

thanks steve,i was trying to pull codes from the climate control so i probably set the light off to blinking,it resets when i cycle the button.
i am really fighting this one,i started a project to see if i could determine why the heads on the 103 lose their hardness and have the car with a restraightened and rehardened head, that runs real good.(i need to go to my origional thread and up date for the forum about the soft heads,man there is just so much time)
i have asked a couple mechanics about the high temp of the 103 while the ac is running and they reply,well they just run hot. in my research on the heads i see that a constant slow cool from 320deg f will soften aluminum,so i set out to check all values. manual says that the compressor should deactivate at 110c(230f) but this compressor never shuts down till the inside temp is satisified and if left idleling the temp will exceed 230f before the aux fan cycles on.
just seems an error to have the controls set so that the head could have such a wide temp swing.
one thing for sure,if your aux fan is drawing its power thru fuse d you should touch it to see if there is heat and if so,mine did ,run a new feed wire fused and solder to the top spring fuse holder.if these engines dont get cooled down you are going to have head problems. this one came to me with a warped and soft head.
last issue,would anyone know the correct part number for the klima relay for this car,vin wdbea90d4kf091637 1989 300te? the one that is installed now is a 002 545 13 05.i do not think this is a problem but i have no way of comfirming.
larry perkins lou ky

[stevebfl]

Your Klima relay has the right number.

I have never had any trouble keeping 300Es below 100deg C operating temp. Something is wrong. I have had a few E320 124 cars that would reach the fan cut in temp and we have modified a couple with parallel resistors to have the fan come on earlier.

[larry perkins]

ok where do i send the apple?
your comment about something being wrong kept me looking even though i didnt quite understand the operation sequence,the slow speed of the fan is driven from the climate control inside panel, after ac turn on the aux fan is suppose to turn on slow and that is what i wasnt getting,no where in the drawings does it show that the slow is driven by the ccu(at least i couldnt find). did a resistance check of the ballast resistor and it was open-duh-.
thanks ,let it idle for 20 min and just a shade over 80 with ac on max, 125 deg f in car,got 58 f from vent at idle.
larry perkins

[stevebfl]

Larry,

You are still misunderstanding this a bit. The AC control head turns the High speed fan on after the engine gets hot. Seems a bit weird I guess.

The low speed fan is directly turned on by the high pressure switrch on the drier. Go check it out. Turn the key on and cross the two wires at the high pressure/temp switch (they are brown and brown and blue I think) the comp high/low cut-off switch is also at the drier and I think these wires (blue and red I think). When the switch is jumped the fan will come on low once the resistror is whole again!.