Faulty Heater / Air con after battery change

I wonder if anyone could offer advise.

I have a 2001 p38 4.6 Vouge, on returning from holiday recently I had a totally flat battery. I removed it and put it on charge but decided to fit a new one as it was a few years old anyway. On reconnection I had the expected keycode lockout messages and window resets to perform. Inserting and removing the key a couple of times cleared the keycode message and the car started first turn.

However, I now have the dreaded "book" image on the heater control, the blower fans are on at full speed and won't respond to manual control, also I have an airbag fault message and the red srs light is lit.

I am hoping to avoid an expensive trip to the dealer and that someone can advise me how to reset these issues otherwise the flat battery could end up being a very expensive problem.

Any help greatly appreciated.

Regards - PJB

does your horn still work, if not you will need a steering couplin..

Hi J,

The Horn works fine, assume you are thinking of the steering coupling affecting the srs warning? Any clues on the heater, the fans at full all the time is driving me nuts! Should I disconnect the battery again or would that make things worse. They really should be designed to stand a battery change now and then.

Regards - PJB

sometimes my srs light comes on i just move the wire going into the becm. sorry dont know about your heating unless its a motor stuck..

peejaybee said:

I wonder if anyone could offer advise.

I have a 2001 p38 4.6 Vouge, on returning from holiday recently I had a totally flat battery. I removed it and put it on charge but decided to fit a new one as it was a few years old anyway. On reconnection I had the expected keycode lockout messages and window resets to perform. Inserting and removing the key a couple of times cleared the keycode message and the car started first turn.

However, I now have the dreaded "book" image on the heater control, the blower fans are on at full speed and won't respond to manual control, also I have an airbag fault message and the red srs light is lit.

I am hoping to avoid an expensive trip to the dealer and that someone can advise me how to reset these issues otherwise the flat battery could end up being a very expensive problem.

Any help greatly appreciated.

Regards - PJB

Click to expand...

Hi....I have been experiencing these problems, but at different times, the SRS could be a loose connection, under the drivers and passenger seat there is a big Yellow connector block, just move the wires and block around a little, ( I used to get this if I adjusted the seat back or forward.....)

As for the Heater, In the late summer mine started to do exactly the same, I have not fixed it as yet, but I removed the solenoid from the Engine fuse box, there are two for the fans...It is the second yellow one back from the front of the engine bay, this has stopped the fan from being on full blast all the time, but it still allows the normal fan and heater to work.......

If someone does know how to resolve this issue, (without changing the complete engine, transmission, and getting rid of the LPG ) I would be most appreciative....


See picture in my profile for correct Solenoid....

j the range said:

does your horn still work, if not you will need a steering couplin..

Click to expand...

Following J's question about the horn I decidsed to test all the functions through the steering wheel and oddly enough when I press the cruise control "set" button the horn sounds!!! (the cruise still works ok too) so something strange is going on all and caused by the battery change. I have never had so much trouble changing a battery in the past!

Also further investigation has shown that it is only the drivers side fan that is on at full blast, the others responding to the heater cointrols as normal.

Thanks - PJB

Check relays 6 and 7, one might be stuck on, and smell the fuse box for burning.

Hi John, which wire going into the becm do you move to clear the srs warning please?

The SRS light is down to the battery going flat and storing a low voltage fault. The fault is common under those circumstances....it can be cleared by a simple reset which will take all of 5 minutes.
Regarding the blower issues, try swapping the front two yellow relays with another of the same colour & shape to eliminate a relay fault. Also make sure that the HEVAC display is not in Manual and "AUTO" is showing. The book symbol is related to many faults ranging from blower motors to stuck blend motors, out of calibration blend motors, faulty sensors, no refrigerant, sticking aircon compressor clutch etc. etc.

I checked relays 6 & 7 and the relays seem ok, but removing 6 certainly stops the fan being on all the time, swopping them over makes no difference so the fault is not the relay, no burning smells either.

I still have the srs light on, and horn sounding when cruise "set" button pressed. I also discovered today that the cd changer has stopped working too. The list now seems never ending. The moral must be not to let your battery die whilst away as this is turning into a nightmare. Everything was ok before the battery died!

I finally got around to forgiving my P38 for its bad behaviour and tackled these problems. i managed to fix the Heater blower motor which was blowing on full on the drivers side only. The transistors on the actual motor were blown and I decided to replace the complete motor with a second hand part. this cured the problem and even put out the "book" symbol on the Hevac display. I hav also cured the CD changer fault with another blown transistor in the power supply for the CD multichanger.

I am now left with the last problem of the horn blowing every time I press the Cruise control "Set" button. I am assuming this must be a fault in the Steering Wheel assembly, (probably another blown transistor/diode as this seems to be the common theme)

Has anyone had this or similar fault? and found a cure.

It's usually the rotary coupler behind the steering wheel that has failed. If you are going to tackle it, disconnect the battery at least 15 minutes before you start if you don't want to risk a face full of airbag and potentially serious injury.

try backing the screws off that hold the horn in place, they will be to tight..

Thanks for the advice Datatek anf J the Range. I have removed the steering rotary coupler and am pretty sure it is faulty as testing the cables with a multimeter i get a short on the airbag cable. (This could explain why I am getting airbag warmings on my message display) there seems to be two types of coupler avaiable - AMR5631 and YRC100350, mine is the latter. Can anyone tell me if these are compatible? - Thanks