P38 2000 4.6 Thor vogue RHD HVAC issue

Hi Everyone, first time poster here. I've been lurking for a while and taking advantage of the wealth of information here which has definitely helped keep my P38 on the road, but now I have an issue which I can get to the bottom of. Any help would be greatly appreciated!

The Hvac was working apart from the right hand recirc motor, which would bring on the book symbol only when I pressed the recirc button. This would clear on restarting the car. It was like this when I got the car and I could live with it, so I left it alone.

Then, about 9 months later the left hand side temperature would not change and the book symbol came on just after start up. I thought it was probably the blend motors so I ordered a set and installed them. I still had the same problem.

The nanocom fault logged: 53 right hand blend motor stall position fault. Current and logged, cannot be cleared. Strange as its the LH that's not working.

On start up it drives the LH blend motor fully opens and closes, then the book symbol comes up.

The RH and distribution motors move when controls are altered but the LH doesn't move.

LH will not move when calibrating but the RH and distribution seem to calibrate ok.

RH motor resistance goes from 1.37 to 5.3 Ohms (grey and white wire)

Distribution motor resistance goes from 1.6 to 3.76 Ohms (grey and white wire)

LH is stuck at 1.48 Ohm and nanocom states 18%

I have a spare HVAC control unit which seems to have the same problem. Both JFC 102550

Has anyone else had a similar issue or any advice on what to try next? I've been struggling with this for days! I just want it to work so I can put the dash back together.

alex230718 said:

Hi Everyone, first time poster here. I've been lurking for a while and taking advantage of the wealth of information here which has definitely helped keep my P38 on the road, but now I have an issue which I can get to the bottom of. Any help would be greatly appreciated!

The Hvac was working apart from the right hand recirc motor, which would bring on the book symbol only when I pressed the recirc button. This would clear on restarting the car. It was like this when I got the car and I could live with it, so I left it alone.

Then, about 9 months later the left hand side temperature would not change and the book symbol came on just after start up. I thought it was probably the blend motors so I ordered a set and installed them. I still had the same problem.

The nanocom fault logged: 53 right hand blend motor stall position fault. Current and logged, cannot be cleared. Strange as its the LH that's not working.

On start up it drives the LH blend motor fully opens and closes, then the book symbol comes up.

The RH and distribution motors move when controls are altered but the LH doesn't move.

LH will not move when calibrating but the RH and distribution seem to calibrate ok.

RH motor resistance goes from 1.37 to 5.3 Ohms (grey and white wire)

Distribution motor resistance goes from 1.6 to 3.76 Ohms (grey and white wire)

LH is stuck at 1.48 Ohm and nanocom states 18%

I have a spare HVAC control unit which seems to have the same problem. Both JFC 102550

Has anyone else had a similar issue or any advice on what to try next? I've been struggling with this for days! I just want it to work so I can put the dash back together.

Click to expand...

If it's the same with 2 HEVAC's, looks like a blend motor problem or the connector at the HEVAC. When you changed the blend motor did you check the flap shaft was free to move and did you get the timing correct between the blend motor and the shaft?

Datatek said:

If it's the same with 2 HEVAC's, looks like a blend motor problem or the connector at the HEVAC. When you changed the blend motor did you check the flap shaft was free to move and did you get the timing correct between the blend motor and the shaft?

Click to expand...

Thanks,

I checked the flaps, they all move freely. Its a new set of blend motors and because I was still having issues I swapped the working RH from the old set onto the LH and it still doesn't work. The new set also came with a new connector.

I'll double check all the terminals are ok in the connector.

alex230718 said:

Thanks,

I checked the flaps, they all move freely. Its a new set of blend motors and because I was still having issues I swapped the working RH from the old set onto the LH and it still doesn't work. The new set also came with a new connector.

I'll double check all the terminals are ok in the connector.

Click to expand...

Take the blend motor assembly off the heater box and see if it works.
The connector I was talking about is the one in the HEVAC not the local one to the blend motor, the contacts have been known to be a problem. Also the connector can appear to be fully seated when in fact it is not and needs a bit of extra force to get it fully home. It's the connector in the photo with all the wires.

Datatek said:

Take the blend motor assembly off the heater box and see if it works.
The connector I was talking about is the one in the HEVAC not the local one to the blend motor, the contacts have been known to be a problem. Also the connector can appear to be fully seated when in fact it is not and needs a bit of extra force to get it fully home. It's the connector in the photo with all the wires.
View attachment 328304

Click to expand...

Thanks!!

Not sure exactly what did it. Disconnected everything, de-pinned some of the connectors, cleaned and squeezed up some of the terminals, put it all back together and and it worked.

All working well. Maybe I'll table the recirc motor at some point. Although, I think it's a big job!

Thanks again