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Anyone with knowledge of how this all works? I dont have heat just in time for winter, want to take the car out to very cold climate for new years.

 

lotus-water-valve.jpg

Where exactly is the water valve located? Is it actually just sitting above pedals?

I think I found the diverter valve on top of the front lower subframe (easy to get to)

I believe grommets #14 or directly behind the pedals and leading thru the body to the diverter valve that above the steering rack (hard to get to)

 

air-solenoids.jpg

Mode Actuator controls the door for the heater matrix?

 

 

Edited by v8GTmac1

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Upgrade today to remove Google ads and support TLF.

Lack of heat is often related to loss of vacuum caused by pipes disconnecting from their rubber elbows, eg 16 & 17 in the above diagram. The vacuum is produced by an electric pump & also controls the cat fast warm up butterfly (on 4 cylinder cars) has that been disconnected or removed? 😊


Cheers,

John W

http://jonwatkins.co.uk

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34 minutes ago, Chillidoggy said:

I don't think the V8 has an electric vacuum pump.

Any idea what produces the vacuum to power the actuators in that case?


Cheers,

John W

http://jonwatkins.co.uk

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Sure PGA was straight off the engine - the 2.2 didnt produce enough vacuum for the flaps to be run consistently 


Only here once

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Check there is a vacuum being applied to the diverter valve (the engine needs to be running), if there is no vacuum the heater matrix will not get fed with coolant.

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5 hours ago, sailorbob said:

Check there is a vacuum being applied to the diverter valve (the engine needs to be running), if there is no vacuum the heater matrix will not get fed with coolant.

diverter valve works

diverter solenoid works

vacuum supply present

found the HVAC module

Poking wires trying to understand where the failure is.........more then likely at the toughest spot, the water valve?

to be continued...........

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HVAC PINOUT TEST:

9  = 11v at 1,   8v at 2,   5v at 3 ,   0v at 4

11 = pos 2   Mode switch

12 = pos 3   Mode switch

4 = pos 4    Mode  Defrost

14 + 15 = heater flap position motor actuation

6 = full v at hottest position and goes down with coldest position

3 = batt volts

7 + 8 = water valve actuation......pin 7 = 12v to cold,   pin 8 = 12v to hot

5 = position of water valve 0-10v    0v = cold  10v = hot

 

 

 

 

Edited by v8GTmac1

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On the wiring diagram, HVAC module pin 4 is connected to a common ground for the HVAC module, flap position switch, flap stepper motor, water valve and temperature sensor.

Have you checked to see if the flap stepper motor is working? The resistors in them are known to burn out.

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On 30/12/2019 at 03:24, sailorbob said:

On the wiring diagram, HVAC module pin 4 is connected to a common ground for the HVAC module, flap position switch, flap stepper motor, water valve and temperature sensor.

Have you checked to see if the flap stepper motor is working? The resistors in them are known to burn out.

i checked everything. In the end it was the Divereter valve, even though I could hear the plunger actuating with vacuum, it wasnt flowing hot water to the water valve. When i pulled the hose off to bypass it, rusty water came out, been trapped there for a while. 

Know  I learned heat is only for the feet and defrost. 

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