Climate control not working

[Arvid]

Starting the QP Evo for this season revealed an annoying problem. There is no life in the climate system. Panel is dead and fan not blowing. The usual loud "click" from AC compressor is also not present. Fuses are checked and OK. There might be some relays involved but the only ones I find are two small ones under the fuse/relay cover in engine bay. Swapping these for others did not solve the problem.

Earlier years I have had trouble with the wires between A-frame and front doors - several of them have gotten brittle and broken off giving various problems. This was checked also and I found 3 new wires broken off. I suspected the mirror temp sensor circuit was involved but repairing the wires did not solve any problems.

Not sure where to go from here and any advice would be appreciated. A fully working climate control and fan is a TüV/MOT requirement or else the car fails and the appointed date is almost here...

 

[Zep]

I guess the first step if to see if you have power to the controller. It seems likely that you don't, so tracing that back is the only way to figure it out.

 

[Arvid]

I will do that. I can add that the climate control acted a bit strange last year. It usually power right up when starting the car but I noticed a few times that it took a while before it started.

I'm waiting for an original QP Evo workshop manual hoping it will show actual relays and connectors for the circuit. The relays I found in the engine bay was was labeled for AC but they seem too small to have anything to do with the compressor.

 

[goranw]

Check if you have 12V to the clima control. Pin out attached. In my case it was a white connector, 4 or 6 pole, I dont remeber exact, on the right side of radio console. 12v goes through this connector and the pin in the connector was burned and caused bad contact. Showed 12V when I measured without anything connected but as soon as connected, so there was some current draw, it went down to almost zero volt.

 

[Arvid]

Thanks for the pin outs. I will check. I actually had same problem with the 4-pin connector you mentioned a few years back. The main 12v wire was burnt. Fixed it and all was ok.

This time it acts in the same way - like it’s the same problem. The repaired wire connection looks solid and with a steady 12v. I’ll check it again but I suspect something else is at fault.

 

[Arvid]

Got some free time today to do some more checks. The pins on climate panel connector are ok. I have good ground on lower left pin and +12v on upper and lower right pin.

Did also check the 20A relay for compressor in engine bay. I think this is for engaging the compressor clutch. Both relay coil and switch function checks out fine. 10A fuse for AC in same fuse panel is also ok. Tried to measure resistance in the compressor clutch coil from the relay socket without getting any result. Could windings be broken ?

A few questions come to mind :

• Should the climate panel come to life just by giving it power on these three pins ? Or are there more to it ? I tried with a power supply on the bench but there is no light or life in the panel.
• Will climate control panel and heating work if the compressor clutch coil has failed ? Or is it part of the circuit in a way ?

I don't know if these climate control ECU's are prone to failing but finding a replacement could be a challenge.

 

[spkennyuk]

Certainly most cars if the compressor is not working the control panel will still light up and work as normal except you will only get ambient air even with the AC turned on.

Ive never known a car that doesnt do that.

 

[Oneball]

Have you tried fiddling with the off button in case it’s contacts have got crappy?

 

[Arvid]

I've tried pushing several times without any difference. Button feels ok but who knows. I'll measure the contacts for the button maybe.

Been puzzling over the climate control panel though. Should it light up when given voltage on the three contacts pr. the pin-out drawing or are there any other contacts that also needs supply ? I tried feeding the panel with a power supply but no life.

 

[Oneball]

Does it normally light up or do the buttons only illuminate with the headlights? @Ewan any idea what your climate control does.

 

[Ewan]

In my general experience, the AC control units of this era of Maser are quite random. But on my current QP IV, it all lights up irrespective of whether the headlights are switched on. But whether that’s “correct” or not is anyones guess.

 

[Ewan]

More importantly, are Arvid and I the only people in the World to simultaneously own QP IV’s and F 400’s?!!

 

[Ewan]

 

[Arvid]

I'm still waiting for the QP Evo WSM. I hope it contains some leads to the puzzle or at least some wiring diagrams.

Ewan,that's a lovely looking 400. Mine is not quite ready for driving yet. It needs a good commissioning as they call it with fresh oil and a good carb tune. I had new hood insulation made and that needs installing also.

 

[Ewan]

That Bruno colour was the original colour of mine also. But for the respray I opted for Prugna, as opposed to sticking strictly with originality.

 

[Arvid]

It seems that the control panel has failed. David Askew has dealt with these problems before and this was the verdict. Should be repairable but needs investigating first.

Should any of you have a spare on the shelf then I'm interested. There are a few for sale worldwide but they are asking a premium for sticky buttons it seems...

 

[Wally]

On Facebook biturbo-group, there is someone (Gareth Kerry) who can repair your panel. (Saw that with a friend, i am not on FB myself)

 

[Arvid]

Thank you. That sounds promising. I'm not on FB either. Any email I can reach him on ?

Edit : I think I found him on this forum - qpv8evo - but he's not been active for many months. Anyone have contact details ?

 

[qpv8evo]

Hello yes not been active for a while but definitely still here and yes can repair the climate panels for Biturbo derivatives
Many thanks
Gareth

 

[Arvid]

Hi there Gareth,

I didn't think FB was good for anything but I was wrong. I found Gareth