Hot and cold cabin fans randomly start and stop

[Jabbah]

The ice warning light is also flickering. Fan controls have no effect and fans are randomly coming on full blast then cutting out. Any ideas where to check? Guessing some water in electrics somewhere.

[pulsarboby]

just had this with mine (may not be the same with yours but worth a shot)
tangueno advised me to check the ribbon from blower motor to switch.....turned out that was ok but problem was the connections to the motor on the multiplug, i had two burnt clips that were obviously making an intermittent connection, clean them all up and spray with wd40 or similar and alls working fine!

the motor is down in passenger footwell just above ecu just incase you dont know.

[Tanguero]

Yep, definitely check the control box in the passenger foot well.

If it is water rather than bad electrical connections, you probably want to get the engine ECU out of the way too - they don't run so well when full of water... (and fix the heater hose that is leaking into it!)

[FUBAR]

While I'm here...my passenger outlet only blows hot air. Im told its probably the diverter? valve/plate? and its a bit of a pig to get to...3-4 hours work. Does this sound right? I can live with it for now but its one of those small jobs that annoys me hasn't been done.

TBF I only remember about it when Mrs Fubes gets in the car and then moans about the heat lol

[PuffsBack]

Jabbah said:

The ice warning light is also flickering. Fan controls have no effect and fans are randomly coming on full blast then cutting out. Any ideas where to check? Guessing some water in electrics somewhere.

Hmmm... My ice warning light has a life of its own (changed the sensor in the nose etc to no avail) however when I purchased another ME0150 heater control box I got exactly the same symptoms as you (annoyingly it solved the ice warning light issue!)

When I disected both ME0150 boxes I found an extra resistor as been soldered onto the circuit board so I suspect something is wrong with the ribbon cable etc and to get it working they have 'botched' the heater control box which has then had adverse effects on the the ice warning light.

I would suspect your problem is with the Heater Control box which is located above the passenger footwell, you will need to remove the carpet mat and then the back panel of the foot well and the box will probably drop down.

[PuffsBack]

FUBAR said:

While I'm here...my passenger outlet only blows hot air. Im told its probably the diverter? valve/plate? and its a bit of a pig to get to...3-4 hours work. Does this sound right? I can live with it for now but its one of those small jobs that annoys me hasn't been done.

TBF I only remember about it when Mrs Fubes gets in the car and then moans about the heat lol

Do you mean the top outlet in the middle or the eyeball near the door?

The vents in the Cerbera don't have diverters - they either blow hot or cold. The passenger eyeball and the driver steering wheel vent should blow cold and the centre windscreen vents blow hot.

In other words if you turn on the hot fan it should make no difference to the amount of air coming out of the eyeballs, however the windscreen vents should blow strong and vice versa, cold fan should make the eyeballs blow strong


There are other vents lower down but off the top of my head I can't remember which blow hot and cold

[FUBAR]

PuffsBack said:

Do you mean the top outlet in the middle or the eyeball near the door?

The vents in the Cerbera don't have diverters - they either blow hot or cold. The passenger eyeball and the driver steering wheel vent should blow cold and the centre windscreen vents blow hot.

In other words if you turn on the hot fan it should make no difference to the amount of air coming out of the eyeballs, however the windscreen vents should blow strong and vice versa, cold fan should make the eyeballs blow strong


There are other vents lower down but off the top of my head I can't remember which blow hot and cold

Eyeball one next to the door. I cant speak for the passenger eyeball (as I've never thought to test it) but the steering wheel eyeball defo blows either hot or cold, dependant on which blower I have switched on.

The vents in the cubby hole also blow hot and and cold. Ive no idea if the windscreen ones work at all lol (well, yes they do but not very powerful and I 'think' they blow hot)

[Tanguero]

I think there are at least a couple of versions of heater plumbing depending on the age of the car. Certainly my '97 mixes hot and cold air from the fans in the cavity behind the dash and distributes mixed air from all the vents and both eyeballs.

I have seen mention of an "udder" shaped air distribution box on later cars - above the drivers feet I think, but mine has never had one with the hoses from the blowers going straight into the cavity behind the dash.

The passenger footwell tends to stay warm because of the heater feed pipes and the drivers footwell stays cold because of the draft from inside the wing.

[PuffsBack]

Tanguero said:

I think there are at least a couple of versions of heater plumbing depending on the age of the car. Certainly my '97 mixes hot and cold air from the fans in the cavity behind the dash and distributes mixed air from all the vents and both eyeballs.

I have seen mention of an "udder" shaped air distribution box on later cars - above the drivers feet I think, but mine has never had one with the hoses from the blowers going straight into the cavity behind the dash.

The passenger footwell tends to stay warm because of the heater feed pipes and the drivers footwell stays cold because of the draft from inside the wing.

Really? What does your manual say? Mine manual explicitly states that there is no mixing and that the vents either distribute hot or cold air

[FUBAR]

Tanguero said:

I think there are at least a couple of versions of heater plumbing depending on the age of the car.

Really? Different setups within 1 model? Learn something new every day



FWIW my heating setup was described to me the same as yours ('98 car)

[FarmyardPants]

Mine's as you say, puff. I have the 'udder' above the removable panel above driver's knees (2000/W reg).

[Tanguero]

PuffsBack said:

Tanguero said:

I think there are at least a couple of versions of heater plumbing depending on the age of the car. Certainly my '97 mixes hot and cold air from the fans in the cavity behind the dash and distributes mixed air from all the vents and both eyeballs.

I have seen mention of an "udder" shaped air distribution box on later cars - above the drivers feet I think, but mine has never had one with the hoses from the blowers going straight into the cavity behind the dash.

The passenger footwell tends to stay warm because of the heater feed pipes and the drivers footwell stays cold because of the draft from inside the wing.

Really? What does your manual say? Mine manual explicitly states that there is no mixing and that the vents either distribute hot or cold air

verbatim (the syntactic error is theirs!)
Page 7 Section 3
"The hot (A) and cold (D) knobs are controlled by separate, infinitely variable speed fans. However both fans can be switched on simultaneously to mix the air to the desired temperature. To turn either fan on press and release the knob, and then rotate clockwise to boost the flow of air to the cabin. The hot and cold air controls will illuminate red and blue respectively when in use"


So yes my manual describes the behaviour of my heater. As I said there are different versions of heater design and I have only just finished reassembling my dash including getting all the air ducting connected back up so I do know exactly how mine works.

[Jabbah]

Thanks for the pointers! Was not quite the issue but definitely the right area. My control box was lacking the box. It consisted of a heatsink the lid of the box and the two circuit boards taped to it with masking tape! The top board was pressing down on and bending a voltage regulator on the "inner" board which was casuing the issue. Added a bit of a spacer and bent the voltage regulator back and all working as normal to get me back from Devon without sticking to the seat

One new problem now though is that towards the end of the journey I started getting wet feet. Either condensation from the air con or it flicked off and a bit of ice started melting. Never had that before though. There is no adjuster knob in the normal place to adjust the air con temp. Whilst looking at the fan control boards there are a couple of resistors soldered between the board on one edge. These broke off whilst fixing the fan issue. Could they be anything to do with adjusting the air con temp? Could just have been a very humid day and cold pipes I guess. It was coming from the pipe where the draft from the front wing comes in...

ETA: The flickering ice warning light has stopped too!

Edited by Jabbah on Wednesday 15th August 10:29

[Tanguero]

As far as I know the fan control board has nothing to so with the aircon temperature setting. The button just sends a signal to turn it on or off.

On my car the temperature control for the air con is cable tied to one of the cross-members right up behind the dash on the right hand side of the steering wheel. It looks like a rheostat with a bare shaft and no knob, but you have to remove the scuttle panel and get upside down in the drivers footwell with a torch to find it. Yours is probably up there somewhere.

[PuffsBack]

Jabbah said:

Thanks for the pointers! Was not quite the issue but definitely the right area. My control box was lacking the box. It consisted of a heatsink the lid of the box and the two circuit boards taped to it with masking tape! The top board was pressing down on and bending a voltage regulator on the "inner" board which was casuing the issue. Added a bit of a spacer and bent the voltage regulator back and all working as normal to get me back from Devon without sticking to the seat

One new problem now though is that towards the end of the journey I started getting wet feet. Either condensation from the air con or it flicked off and a bit of ice started melting. Never had that before though. There is no adjuster knob in the normal place to adjust the air con temp. Whilst looking at the fan control boards there are a couple of resistors soldered between the board on one edge. These broke off whilst fixing the fan issue. Could they be anything to do with adjusting the air con temp? Could just have been a very humid day and cold pipes I guess. It was coming from the pipe where the draft from the front wing comes in...

ETA: The flickering ice warning light has stopped too!

Edited by Jabbah on Wednesday 15th August 10:29

If possible can you send me a photo of where the voltage regulator is - I am determined to get to the bottom of my 'ice warning light' issue

[FarmyardPants]

while we're on the subject of the heater control box, mine had the two circuit boards floating around inside, so I joined them together with rawl plugs and screws, pic below. Now much easier to connect/remove the plugs

[PuffsBack]

FarmyardPants said:

while we're on the subject of the heater control box, mine had the two circuit boards floating around inside, so I joined them together with rawl plugs and screws, pic below. Now much easier to connect/remove the plugs

Thats utter genius! Much better than those stupid tabbed things covered in glue.

[Gazzab]

All of my (98, 99, 02) have had separate hot n cold outlets with no mixing.

[robsco]

My '97 car mixes hot and cold through all vents, like Tanguero's.

[FUBAR]

I'm firmly of the belief it has nothing to do with year of manufacture, but which day of the week the car was finished on

edited for speeeling

Edited by FUBAR on Thursday 16th August 10:51