Climate control issues
 

87 300E W124, heat won't kick in on cold days (30's F) until the engine temp reaches at least 80 degrees C . On warmer days (50's F), heat kicks in when the engine temp is warm enough to be used for cabin heat.

Anyone got any ideas on what's going on? Seems like a short...

Thanks guys.
Cam
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C'mon, noboby's got any ideas?
Cam

Sounds like you have a temperature sensor that has drifted in value.


Let the car sit until the engine is at ambient temperature. Use an ohmmeter to measure the resistance of the sensor, and compare it to the reading that you are supposed to get for the given ambient temperature.

There is a chart that plots the various values for the NTC (negative temperature coefficient) sensor.

I posted one here for my W126, I am not sure of this but I would not be surprised if the values are the same for your sensor, but you will want to verify that.

Here's the thread where I posted that chart, again make sure it applies to your car.

http://www.peachparts.com/shopforum/tech-help/239276-hard-start-when-warm.html


Good luck.

TP, you're the man.
thanks for your input.
I'll give it a try.
Cam

actually, on the 124 that's how it's supposed to work....I hate it myself..but that how it works.....does what it wants....you, the driver, are an idiot and don't know how to control your interior environment...I will do this for you

Tinypanzer, you lost me with your suggestion in re: the CTS as a possible fix for the OP's climate control system. Inasmuch as the two thermistors in the CTS provide signals for the KE controller and the EZL controller, neither of which have an effect on the CCU, what's your thinking about how a bad CTS will lead to the no heat condition from the CCU? I'm not doubting you, just need clarification of how that could be the cause.

So, I tested all sensors and they all are drawing appropriate ohms. I'm figuring it may simply be a bad blower/regulator and may start there. Could it be that a cold blower can't draw enough current to run until it warms up? Because once everything is warm (now approaching closer to a 30 min period) everything functions without issue.
...the investigation continues...
Thanks guys