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Hi, I have a 1991 Bentley Turbo R and the cruise control dosn't work and the heater dosn't blow hot air when doing about 70 mph, just wondered if these were common problems and any ideas what they might be ?? Thanks
 

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In older Spurs like my 1987.5 and most cars cruise control failure could be a brake light bulb is burned out . Or the solenoid/speed regulator, whatever people call it, has gone bad and needs replacing or its a fuse. Heater have no idea.
 

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CAR3Y said:
Hi, I have a 1991 Bentley Turbo R and the cruise control dosn't work and the heater dosn't blow hot air when doing about 70 mph, just wondered if these were common problems and any ideas what they might be ?? Thanks
Could be a vacuum leak in the feed to these devices.
 

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I think they will be different problems.

Speed control - Check brake light bulbs and relays.

You will then need to check the ecu is getting all the correct signals.

The speed sensor for the speed control is at the back of the gearbox and different to speedometer one.
 

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Paul Yorke said:
I think they will be different problems.

Speed control - Check brake light bulbs and relays.

You will then need to check the ecu is getting all the correct signals.

The speed sensor for the speed control is at the back of the gearbox and different to speedometer one.
 

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cruise control and heater.

I have a 1989 Mulsanne S, as I have worked on her for 18+ months I find that most problems are corroded connectors. A lot are Aluminium to Brass, they fur up due to electrolytic action. Replace with insulated All Brass spade connectors. Gary
 

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Hi ,
I have a similar problem in that every time I exceed 50mph in Turbo R the interior heating feeds cold air. When I slow down it returns. It is speed related since I happens at the same speed irrespective of outside ambient temperature.

Did you ever get a fix..

Shemas
 

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The heat issue is a common fault - the reason you start to get cold air is because your heater tap needs replacing.

I think the reason for this is something to do with the spring that keeps it open becoming weak (ie it defaults to open) - the additional pressure in the cooling system (because the engine is at higher rpm) at higher speeds then starts to close the tap, thereby cutting off hot coolant to the matrix. Or something along these lines.

Anyway - you need a tap, it's not to hard to replace. Can be awkward to get at though.
 

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Would you please explain where that tap is?

Mine is a 88 Spur. It never really pumps out more than slightly warm air.

Thanks!
 

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Would you please explain where that tap is?

Mine is a 88 Spur. It never really pumps out more than slightly warm air.

Thanks!
Before you go digging in to the heater tap you need to make sure that your car is actually heating up to normal operating temperature. Where is the needle on your temperature gauge coming to rest once the car has warmed up?

Take a look at the article, Thermostat Issues and Selection, and see if your car is behaving in a manner similar to Don Elliott's was. There are lots of "insufficient heat" problems caused by the fact that a thermostat has failed in the open or partially open position, meaning that coolant immediately begins circulating through the radiator and the car never really warms up adequately.

If you look at items #49 & 50 in this component location diagram for the HVAC system you'll see where your heater tap solenoid is located.
 

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Of course, as listed on my site, if you lose heat at high speed, which returns at slower speeds - it is the water tap. But, if you are one of the very few like myself that finds $200+ to be a lot of money, all that really needs to be changed is the monovalve easily accessible inside the water tap/"heater control valve". It is meant to be able to be changed and is Bosch part number 1 147 213 007 called "Mono Valve Repair Kit". It is about $33, and used in many Mercedes, BMWs, etc.


- Larry
http://mutley.hypermart.net/RollsSubstituteParts.html
 

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Thank you very much to singlemalt for the reply to my post which proved correct . I was quoted recently £1,450 to replace heater matrix as it was blocked but that did not seem logical to me so I resisted.

Then searched for a solution and re-found my post and the answer. Was made more logical when the heater cut off when simply revving the engine. I stuck to the problem description given by singlemalt and despite resistance from the garage the following email arrived..

We have liaised with our technical department regarding the heating system in your Bentley ,which they had advised fitting a heating tap to the matrix as there was a possibility that there was a breakdown of the magnetic field which controls this ( almost like your thermostat )

Wow .... A magnetic field ... It sounds so scientific to little old me ...
Any great result ..thanks again singlemalt
 

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On my recent purchase 1993 Turbo R I also have a malfunction. When I set it kicked in a few minutes later when I didn't want it, Most disheartening.
Any obvious areas to check?
Adam, London-UK
 

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Thank you very much to singlemalt for the reply to my post which proved correct . I was quoted recently £1,450 to replace heater matrix as it was blocked but that did not seem logical to me so I resisted.

Then searched for a solution and re-found my post and the answer. Was made more logical when the heater cut off when simply revving the engine. I stuck to the problem description given by singlemalt and despite resistance from the garage the following email arrived..

We have liaised with our technical department regarding the heating system in your Bentley ,which they had advised fitting a heating tap to the matrix as there was a possibility that there was a breakdown of the magnetic field which controls this ( almost like your thermostat )

Wow .... A magnetic field ... It sounds so scientific to little old me ...
Any great result ..thanks again singlemalt
You have to be very careful as many people do not properly understand these cars. Very easy to waste money on them!
 

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I fixed my cruise control by replacing the ecu unit located under the dash by the steering wheel,got one for £50,it appears they are prone to pack in
 

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when my cruise control stopped working recently, I traced the fault to the brake pedal "OFF" stop, It manifested itself by the brake lights remaining on and thus disabling the cruise control.
The fix was to adjust the "brake off" stop in the rattrap by judicious bending the stop plate with a sturdy screwdriver, thus ensuring that the brake lights went off whenever the brake pedal was released, and thus restoring the cruise control function. cost of repair..nothing.!
 

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hi quite often its the speed cruise bellows does not work .it could be a air leak on the bellows.the easy way is diconnect speed cruise chain start car up and disconnect wires and then power it up with a live and a earth if the bellows pulls in you know that works ,if that works i could be your stop light switch dont be mislead by your stoplights still working.stoplight switch is located in the rat trap under the drivers floor hope this helps
 
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