Open Book Symbol ! 1998 P38 4.6HSE

Hi All

The above symbol has started to appear on when the engine reaches operating temperature. The air compressor clutch is functioning correctly and the flow and return pipes appear Ok (one warm the other cold). The temperature at the outlets in the car appears to be OK.
Any suggestions would be welcome.

Regards
Safeman

It usually a blend motor or flap solenoid that is not working or stuck. Check to see if you have full functionality in air flow to the windscreen, fascia, footwells.

Try all of the settings, does both sides of the heater go from hot to cold ok?, if not it`s one of the blend motors. Does the distribution buttons work?, if not it`s probably the distribution motor thats faulty. If all of these are ok then it may be the heater core temperature sensor.

Hi All

I have tried all the settings suggested and the distribution appears OK for all positions as do the temerature settings variation from lo to hi. Can you please advise where the heater core temperature sensor is situated and is the replacement a DIY job.

Regards
Safeman

Safeman said:

Hi All

I have tried all the settings suggested and the distribution appears OK for all positions as do the temerature settings variation from lo to hi. Can you please advise where the heater core temperature sensor is situated and is the replacement a DIY job.

Regards
Safeman

Click to expand...

According to RAVE, the heater coolant temperature sensor is attached to the outside of the coolant input pipe, next to the heater matrix.

HEATER TEMPERATURE SENSOR
Remove
1. RHD vehicles. Remove fascia closing panel to gain access to sensor. See CHASSIS AND BODY, Repair.
2. LHD vehicles. Open glove box. Remove 5 screws securing glove box liner to fascia.
3. Release glove box liner. Disconnect lamp multiplug.
4. Release cable from glove box latch.
5. Lower glove box liner from fascia to gain access to sensor.
6. All vehicles. Disconnect sensor multiplug.
7. Release clip. Remove sensor from heater feed pipe.

Refit
8. Reverse removal procedure.

At the compressor, one pipe should be freezing and the other one too hot to touch with the aircon running. Are yours like that?? Could be low on gas.

If your car is a r/h/drive, it would be at the back of the facia panel of the center console. It is attatched to the heater pipe just before the pipes enter the heater. Now i haven`t tried this myself but i am told that they can be arkward to get to to remove, so i have been informed that a new sensor can be fitted a little further away from the heater using heat sink cement as used to fit heat sinks to cpu`s in pc`s. When dry disconnect the cables from the old sensor and fit to the new. As i said i personally havent tried this but i have been told it works.
Hope you sort it.
Mark

Safeman said:

Hi All

and is the replacement a DIY job.

Regards
Safeman

Click to expand...

Yes, its a diy job takes about 2 hours on a RHD vehicle, which includes serveral coffee breaks:

Tools required:
+ head screw drivers, small flat blade screw driver, mirror on a stick, kneeling pad and a torch.

1. Remove the 2 screws holding the electric window control panel and lift panel to gain access to the next screw.
2. Remove the single screw holding the gear lever panel, lift and rotate the panel as required to gain better access to remove trans side cover panel.
3. Remove the transmission tunnel side cover panel.
4. Remove the cover panel under the steering column.
5. Remove the cover panel above the foot pedals.
6. Remove the triangular air vent (just pulls off) and its mounting tube held by 2 screws.

The temp sensor is on the lower pipe, look above the foot pedals to the left follow the pipe back and you can just see the blue connector plug.

To release the clip holding the sensor look up between the heater box and the heater pipes from besides the trans tunnel use a flat blade screw driver, then pull the sensor of the pipe and remove the wiring plug.

Connect the wiring to the new sensor, place arm along the top of the foot pedals with your hand through the space uncovered by the cover above the foot pedals, your other hand goes up just in front of where the triangular vent is/was located. Fit the sensor with your right hand, now hold the sensor still with your left hand, push the retaining clip over with your right hand, the sensor can still be moved/positioned as required.

Replace cover panels.

More info here: Range Rover P38/4.0/4.6 Common Problems and Fixes

The sensor costs about 16.00 GBP


hth

zzr

I have now checked the pipes at the compressor one is freezing the other is only warm not too hot to touch as suggested. Does this indicate its low on gas?

Could very well be. Get the gas level checked before jumping to any conclusions.

I am assuming that you are in the uk, if so try taking your car to Kwik fit. Now i know a lot of people dont like them but they do a really good deal with aircon regassing. They will check the temperature then recharge the system and if the temperature doesnt drop by a certain ammount you dont have to pay. If it does i think it costs around £45.00 inc vat, they also do a leak test in with the service. I replaced my condenser so the system was definately empty they flushed it, filled it and done a leak test all for the £45.
Hope this helps
Mark