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fly735
03-15-2004, 02:17 AM
Hi guys im new to the game so please bear with me... i know yo've probably heard it over and over again about HVAC's but my problem is a little different. The blower wont turn off... even when the knob is on the 0 position... the microswitch was removed and cleaned and seem to be working fine... can anyone please give me an idea on whats wrong and what should be done? any sugestions will be appriciated.

Cheers, Sam

elmorekevin
03-15-2004, 10:20 AM
There is a relay mounted on the blower motor housing underneath the cowl. It it was stuck in the "on" position, would it cause the blower to continually run?

There are two relays, one is for the compressor, one is the blower motor, I can't remember which is which.

Just some thoughts,
Kevin Elmore
'86 735i
223,500 miles
Virginia Tech
<img src="http://www.***********.com/members/vtbimmer/Rear.JPG">

fly735
03-15-2004, 05:05 PM
so do i just change the relay or is there something else i should look for? I thought it might have to do with the transistor pack that runs the blower... mind you this problem just started happening out of nowhere... it was working fine before...

Thanks, Sam

elmorekevin
03-15-2004, 05:10 PM
They're just the regular bosch relays, easy enough to test. That'll be much easier to do than looking at the transistor pack. Let us know.Kevin Elmore
'86 735i
223,500 miles
Virginia Tech
<img src="http://www.***********.com/members/vtbimmer/Rear.JPG">

clinta74
03-15-2004, 06:03 PM
My guess is that it could be a problem with the DEFROST circuit. The fan defaults to high and the fan switch is bipassed with defrost.

fly735
03-15-2004, 11:35 PM
Bad news, the relays were tested and working, i even replaced the relays with some from a donor car (looked much newer) and still the same problem.

The blower doesnt also run at full blast. When the volume knob is moved to the highest setting it gives just alittle more power... and also my vacum pump doesnt stop when the engine is on... if that information helps...

Any help is greatly appriciated

Thanks, Sam

Draleu
03-16-2004, 11:41 AM
If you vacuum pump never stops you have a vacuum leak somewhere in the system. That is a separate problem from your blower. Does your air blows out of all the right vents?
You said your microswitch is fine, did you test it with the wheel in place and make sure there is a break in the contact when off?
On fan speed, try cleaning the wheels' sliding contacts. If still not working it is your transistor pack.

fly735
03-16-2004, 08:20 PM
The air only comes out of the vents for the window, for defrosting, even when something else is pressed i.e. Auto heater, up/down the air keeps coming from the defrost vents... i have disconnected the blower so it wont die out. i hope the problem isnt to big. Also if anyone can direct me or tell me how to check for vacuum leaks to help with the pump, that'll be great. Starting to get cooler here need the heater and defrost to work properly.

Thanks, Sam

clinta74
03-17-2004, 11:53 AM
<a href="http://bimmer.roadfly.org/bmw/forums/e23/4206981-1.html">Finding HVAC vaccuum leaks</a>
<a href="http://bimmer.roadfly.org/bmw/forums/e23/4206818-1.html">Hvac switch/light problems</a>
<a href="http://bimmer.roadfly.org/bmw/forums/e23/4202020-1.html">More HVAC light problems</a>

Draleu
03-18-2004, 06:19 PM
This is going to be a long one since you have big vacuum leak(s). You are going to need a hand vacuum pump with a gauge. Over here you can borrow one from Autozone. From here on in, the right side is passenger side if you have a left hand drive.
Start with the easy stuff - the check valve in the intake manifold area and the heater servo on the right side of the firewall. Make sure yor vacuum is going only one way towards the inside of the car. If the servo does not hold vacuum you will need to get it replaced or plugged it if you don't need heater. If that still does not cure your leak move on up to the cowl area. Pull up the rubber strips and you will see the screws that are holding in the cowl cover. Gently lift the cowl and move the wiper fluid hose out of the way. I usually just lift it up high enough to reach in and check the T connector on the right side. Also check the two servo on the flaps. The lft side servo is two stage sevo so you will need to check both ports. Also on the right side check the black egg crate container(vacuum reservoir) for leak.
If that still does not solve the problem you will need to go inside the car which is a PITA. You can email me direct if you have questions.

fly735
03-19-2004, 02:38 AM
Got a day off work tomorrow, might check for vacuum leaks. Something werid happened today, i rechecked that none of the blower conections were corroded or disconnected also checked the fuses, and while the blower was running i removed both relays and its was still running!! is this normal? Or might someone know what the problem is? when you go into deforst mode does it also bypass the relays?

Thanks heaps to everyone thats helped me out :)

fly735
03-23-2004, 03:04 AM
Just fixed the HVAC, changed the transistors (took some time and effort but well worth it) thanks to everyone for there help. I appriciate it heaps.

richard
01-30-2006, 10:06 AM
found the leaks, turned to be the vacuum motors that operated the foot and face vents. i understand the the dash has to be removed to repair these. is there a way to lock the open?

goms187
01-30-2006, 12:11 PM
i have heard this weird clicking( probally a relay) behind the contorl panel for the hvac in my car it tends to happen when in heat up/down and the fan selector towards max, dosnt do it when its in defrost mode. Any ideas?http://forums1.roadfly.com/preferences/showsigimage.php?img=136557
83 733i 5 Sp


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