E34 Question
 

About a year ago, when the radiator cracked, I considered the 93 525i to be done for and handed it back to my dad and upgraded to an 02 530i. He decided it had some life left in it and splits time between it and his M3.

Yesterday while he was driving home from the lake, he noticed that the heat had stopped working. After playing with the settings, the heater engaged only when it was on the full max settings (all the way to the right). After only a few minutes it was unbearably hot and he toggled back and forth the rest of the way home.

After some initial research it looks either the Heater Valve or a blower resistor. Any input or personal experience from the brain trust would be greatly appreciated.

Vote for heater valve. Blower resistor just screws with how the fan operates. They fail on BMW's

rjp

iirc the heater valve pulses via a frequency signal which makes it open and close depending how hot the heat is set......full heat holds it open.....

Thanks, I will let pops know its the heater valve...maybe I will even head out his way this weekend and help him mess with it.

I am a bit confused. Is the temperature control inop or is it the blower. If blower than it is a bad final stage resistor. Common problem. BMW E34 Website

Let me see if I can describe the symptoms a little bit better.

With the heat on moderate settings, it blows cold air. The second the dials are pushed all the way to the right (past the point where the sliders "click" for those familiar with bmws of that vintage) to their full max flow settings, the system begins blowing extremely hot air.

That is the extent of the info I have at the moment.

Heater control valve, that's my vote.