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-   -   E36 328is heat blowing..on and off? (

noodles101 09-26-2011 01:31 AM

E36 328is heat blowing..on and off?
sooo i recently got new rad , coolant over flow tank, and got everything bled out properly i think.
( i check almost every morning and the level is good )

and when i set it to 25 degrees with heat, the heat blows quite well for about 10 mins and the heat would go away...and then heat come back..

its on and off, im not sure what the problem is?

anyone have similar issue?

jon.e 09-26-2011 07:45 AM

Ya. This is a common problem. Google it. Its a resistor somewhere in there. I had the same problem but i got it fixed for free from one of my friends. I belive u can buy the resistor at radio shack. Less than a 10 dollar fix.

noodles101 09-26-2011 07:48 AM

thanks dude, glad its not a big problem.
lol i always freak out every time something has to do with my heat :

i automatically think -- cooling system / rad / heater core / water pump./ t stat / ..LOL

jon.e 09-26-2011 08:05 AM

Ya, trust me i feel u. I was worried too, aslong as ur temp is half way everything else should be fine. Im sure other members have had this problem before. Hopfully someone can post a DIY for this.

Singe 08-16-2012 04:11 PM

I just experienced this this morning. Can any one post a DIY or better explain what resistor and where is it located.


DET1990 08-22-2012 07:51 PM

the resistor is called the final stage unit
and it is located in the near the gas pedal but behind the lower dash panels

so you remove the dash panels and you will see the ducting for the heater system and it is in that area

my fan didnt blow at all and i changed that and if fixed it

this is the diy i followed

BmW1819 08-22-2012 10:02 PM

Is it heat or your blower on and off? ? And it a digital display right??

doogee 08-22-2012 11:19 PM

Sounds like the system needs more bleeding to me...

DANIMAL 08-23-2012 09:05 AM


Originally Posted by doogee (Post 1579589)
Sounds like the system needs more bleeding to me...

+1, if it is the heat that is going on and off, and the blower remains constant.

If the blower is turning on/off or weak at lower fan speeds and blows hard on high then its likely your final stage unit.

If it is intermittent, even on full, and you have a digital climate unit, you may need to replace a resistor inside.

If those two fail then you may need a new blower. You can test the blower directly using the plug to your final stage unit. Research the pinout; I diagnosed a final stage unit failure by jumping the terminals. You should be able to test every speed of the unit. Don't leave it jumped too long, it takes a lot of amperage so the wires/jumpers will get hot quick.

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