No heat from passenger side

Tiny
NOTHING.LEFTTOCHOOSE
  • MEMBER
  • 1995 BMW 740
  • V8
  • 2WD
  • AUTOMATIC
  • 118,000 MILES
1995 BMW 740iL:

Passenger side heater does not produce heat. Driver side does. The fan works for both.

Last 7 of VIN: DH32948
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Sunday, November 28th, 2010 AT 7:41 PM

9 Replies

Tiny
ERNEST CLARK
  • EXPERT
May have a stuck blend door or leaking vacuum line/solenoid or electrical connector. Also, check the switch/controls on the passenger side. If the problem isn't in the switch, you'll have to remove the HVAC unit and inspect the blend door and it's controls.
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Sunday, November 28th, 2010 AT 7:45 PM
Tiny
NOTHING.LEFTTOCHOOSE
  • MEMBER
The switch on the console, for temp and fan speed all work. Can you point me in the right direction to inspect the HVAC unit?

Thanks!
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Sunday, November 28th, 2010 AT 7:47 PM
Tiny
ERNEST CLARK
  • EXPERT
If you aren't already familiar with this procedure, I don't recommend you do this yourself. However, if you do want to do it, I recommend purchasing a repair manual for your car. It'll have ilustrations that you can refer to as well as helpful hints.

Here's the repair procedure. (It's pretty involved)

Unfasten water hoses (1) to end panel. Carefully blow out lines to clear remaining coolant from heater.

Draw off coolant and unfasten both tubes (2) on the end wall. Unfasten screws (3) on the end wall.

Remove steering column.

Remove trim from instrument panel.

Remove center console.

Remove reinforcing tubes from left and right sides.

Remove heater.

Installation:
Do everything in reverse. Hopefully you kept track of all the bolts.
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Sunday, November 28th, 2010 AT 7:58 PM
Tiny
DR. HAGERTY
  • MEMBER
Robert Bentley publications has an excellent manual for the E-38 body style cars. I agree that the blend or heater door is not opening and it may be an actuator, the proprietary scan tool from BMW has the ability to go to the level of seeing whether or not all the doors are opening and perhaps it has logged a fault that the proprietary scan tool could bring up and point you in the correct direction and allow the most efficient use of the repair time.
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Sunday, November 28th, 2010 AT 9:16 PM
Tiny
DR. HAGERTY
  • MEMBER
As soon as I hit the send button, I realized the issue might also be the heater control valve on the firewall, feel the output tubes during operation to see if they are allowing hot water to flow through.
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Sunday, November 28th, 2010 AT 9:19 PM
Tiny
NOTHING.LEFTTOCHOOSE
  • MEMBER
Thanks.

Could you tell me where to locate the output tubes?
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Sunday, November 28th, 2010 AT 9:22 PM
Tiny
DR. HAGERTY
  • MEMBER
The heater control valve is on the firewall, just left of center behind the engine top cover, there is one in, and two out tubes. Feel them all at operating temperature and see if they are getting hot water flow.
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Sunday, November 28th, 2010 AT 10:14 PM
Tiny
NOTHING.LEFTTOCHOOSE
  • MEMBER
Care to forward a diagnosis if the tubes are cold? Hot? One each?
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Monday, November 29th, 2010 AT 7:27 AM
Tiny
DR. HAGERTY
  • MEMBER
Lets get past the "if" When you have the facts, let me know.
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Monday, November 29th, 2010 AT 5:51 PM

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