heater doesnt work!

[Chriskbmx]

so i just got this car and just got it running to find out the heat doesn't work. i have no idea where to even start. but it needs to work because the winters are cold in pa lol. it doesn't turn on no matter what setting it is on. any ideas?

[jlevie]

What year car? And what part of the heater doesn't work, the blower or basic heat?

[Chriskbmx]

its a 1991. 318is. i just removed all the airconditioning parts int he engine bay if that makes a difference. and the blower doesn't work at all. what do u mean by basic heat?

[dnguyen1963]

If your blower does not work then you will not get any heat output from the heater core into the cabin. Get to your heater core (inside the car under the dash...there is diy instructions) and feel it to see if it is hot. If yes, then troubleshoot your blower. It might just be the blower resistor that needs replaced.

[noneya54321]

I would also check the K7 Relay under the hood. that was my problem with the car i bought Saturday.

[Chriskbmx]

where is that relay located upder the hood and how do i go about checking it? i can do engine swaps and stuff but i am just learning about relays.

[Zinno_e30]

Check fuse before you do anything.

[Chriskbmx]

yeah im going to. we will see wha i can do.

[Quadrajet]

After you've checked to make sure your electrical is in order, you may want to see if you're getting warm coolant to the heater core. Next to your Brake booster is where those hoses are, give them a feel and see if coolant is circulating. If not, you may need to add coolant or properly bleed the cooling system.

I also see you removed the AC. That may have some bearing on your problem if the AC system is like the GM systems I've worked on. But since I haven't messed with any on my BMWs, I'll let someone more experienced speak on that.

[Chriskbmx]

thanks man. and that is what i was asking, i wonder if there is any wires i need to splice together or something.

[Quadrajet]

I know on the GM systems that there was a plug attached to the clutch, I thought it was just for the clutch actuation, but it wasn't. With that disconnected or the pump removed the heater blower would just "idle". I'll go out and take a peak at a 318is I'm parting and see what's there.

[Quadrajet]

OK went and looked at the car I'm parting, then looked at my wiring diagrams. Looked like that wire to the compressor wouldn't have anything to do with the blower motor. So I went to my daily driver and umplugged that wire, my thought was correct, I still have all speeds on my blower.

So you're left with Fuse-Relay-Switch-Resistor-Motor to check. I have a hunch it may be the points in your resistor, if it's not the fuse or relay, but ya never can tell till you poke around.

[Chriskbmx]

see im just thinking if it was a resistor issue it should run at the highest speed right? because its not resisting current. so that leaves me with fuse, relay, switch and motor.

[Quadrajet]

That tends to be the general consensus. I would check the fuse, relay and then the switch first, they're easier to get at. Then check the resistor.

There was another thread last month where someone didn't have any speeds and renewing the points brought it back, but that's the first I'd heard of total loss, from the points.

[Chriskbmx]

whats the points? i can tell you anything drive line related but when it comes to testing switches and relays im lost. any help in this area of testing?