STOP light and red high engine temp light flashing

Nuneatonrob · Post by **Nuneatonrob** » 23 Sep 2008, 12:08

Hello again. I found out how to get my clocks out on my Xsara, and discovered that the STOP Warning bulb and the high engine temp warning bulb had been removed!!! I have replaced the defective / missing bulbs in the clocks now, but have a problem with the STOP and high engine temp warning light flashing intermitently. My guess is this is why the bulbs had been taken out!!

I can't see any reason for these two warning lights to be flashing, as the engine temp rairly exceeds 90 degrees on the gauge, and the car runs fine, and there is plenty of coolant in it.

My question is this....is there a sensor in addition to the temp sender that sends a signal to the dash warning of excessive engine temp on a Xsara HDI 90 SX, and if so where is it located??

I want to have all the bulbs and warning lights in place, but if I can't find out why this is happening, may have to revert to the Heath Robinson approach and remove them again as a dashboard flashing like a Christmas tree for no apparent reason is annoying!!

Any response is welcome!!

Thanks all.

Rob

Post by **CitroJim** » 23 Sep 2008, 12:33

Hi Rob,

On a non-aircon car, there are usually two temperature sensors on the thermostat housing. One for the temperature gauge via the engine ECU and one for the high temperature warning light. In aircon cars, the thigh temperature warning light is controlled via the Bitron Sensor and Bitron ECU.

My first thought is that you have the usual dirty/intermittent connection problem on the Bitron Unit. If you have aircon, are your cooling fans working OK?

Not sure where the Bitron unit is on a Xsara. In other Citroens, it lives under the N/S headlight and therefore gets damp on a regular basis.

Nuneatonrob · Post by **Nuneatonrob** » 23 Sep 2008, 13:09

Hi, thanks for the reply,

My car has Aircon, and to my knowledge the cooling fans are working fine, as I can hear them slowing down if I switch of the engine when the A/C has been running..

As you mention it, I noticed the other day I turned on the A/C then on my way home the lights were flashing away for the entire journey home.....I shall go and test it now, and see if turning on the A/C has any effect?

By the way what is the bitron unit? how would I go about identifying it??

Thanks very much.

Rob

Post by **CitroJim** » 23 Sep 2008, 13:27

Nuneatonrob wrote: By the way what is the bitron unit? how would I go about identifying it??

The Bitron Unit Rob, is a little unit that on A/C cars, controls the fans and interlocks their operation to the aircon. Basically, it is responsible for turning the fans on slow when you press the A/C button and letting the A/C ECU that the fans are running so that it can safely engage the compressor.

the Bitron also brings the fans on if the engine runs hot (independant of the A/C), slow at first and then fast if the engine gets really hot. It reads termperature information from the brown sensor on the thermostat housing. A tertiary function is to light up the high temperature warning light.

The Bitron itself is a small box with a multi-way connector on it, often stashed away in a damp and inaccessible place! Someone will tell you where it is on the Xsara Rob.

Xaccers · Post by **Xaccers** » 23 Sep 2008, 13:30

I know you've said there's plenty of coolant, but just for people's information, Cassy's lights do this when her coolant level drops.

Nuneatonrob · Post by **Nuneatonrob** » 23 Sep 2008, 13:40

I have just checked, and with the A/C on, the high temp light flashes, turn it off and the light goes out too.

Checked collant and this seems fine, and the fans come on slow with the A/C on...

Thanks for the help so far I'll keep you updated!!

Cheers,

Rob

wheeler · Post by **wheeler** » 23 Sep 2008, 13:53

Nuneatonrob wrote:Hi, thanks for the reply,

My car has Aircon, and to my knowledge the cooling fans are working fine, as I can hear them slowing down if I switch of the engine when the A/C has been running..

Are both of the fans working though ? if one fan is faulty it will bring on the stop light when the other one is working.
I think (not 100%) the bitron unit is behind the front bumper under the n/s headlamp area on the xsara.

Nuneatonrob · Post by **Nuneatonrob** » 23 Sep 2008, 14:29

I'll double check the fans later....to be honest I haven't looked at them, only heard them....visual check required me thinks!

Thanks for your help guys

Rob

Clogzz · Post by **Clogzz** » 23 Sep 2008, 15:08

Unnecessary STOP and overheat indications come from bad contacts between the Bitron and brown temperature sensor.
Had the STOP and overheat lights coming on intermittently on the Xantia, caused by a bad crimp contact in the plug/socket going through the inner wing, near the battery.

Post by **admiral51** » 23 Sep 2008, 23:08

Just to add to Clogzz reply i have had a similar problem with my Xantia giving phantom stop/temp warning symptoms. when this happened both fans cut in at full tilt turned out the brown plug on the thermostate housing had bad contacts from a previous cut n splice since doing the job correctly ive never had any problems

Colin

uncle buck · Post by **uncle buck** » 24 Sep 2008, 07:53

Rob,

We had the same problem on our Xsara & it was caused by the radiator fan not working on the slow speed....it wasn't working because of the resistance coil that controls the slow speed had corroded & broken....Maybe yours is the same.

Have a read through the thread below...for details (page 2).

>>CLICK HERE<<

Hope this helps.

PS.
Go into your "Profile" & put your car details in your signature....everyone then knows what car you have & can offer more detailed advice

Cheers.

Nuneatonrob · Post by **Nuneatonrob** » 24 Sep 2008, 10:39

Thanks for all the advice so far guys...I shall have a look this evening if I get a chance, and report back any findings..

The coils are located in the fan surround then is that right?

I shall have a poke around and see what I can find...

I'll let you know.

Cheers guys,

Rob

uncle buck · Post by **uncle buck** » 24 Sep 2008, 10:43

Nuneatonrob wrote:Thanks for all the advice so far guys...I shall have a look this evening if I get a chance, and report back any findings..

The coils are located in the fan surround then is that right?

I shall have a poke around and see what I can find...

I'll let you know.

Cheers guys,

Rob

Yeah the coils are in the fan surround....I just removed the grill from the front of the car & then I could get to them.

Hope this is your problem as it's an easy fix.

Good luck.

uncle buck · Post by **uncle buck** » 24 Sep 2008, 10:58

Just had a look on the Citroen service site & your car (MK1 Xsara) doesn't apear to have the coils & has a different set up....Sorry if I built your hopes up.

There is a post somewhere on the forum that has a link in it to how the system fitted to your car works...I'm sure it is a detailed description of how the fans work on a Pug 306 but I think it will cover your set up.

*** EDIT****

>>HERE IT IS<<

Cheers.

Nuneatonrob · Post by **Nuneatonrob** » 24 Sep 2008, 19:04

Right I have checked the fan operation, and it doesn't look great.

The right hand (when looking at the front of the car) fan cuts in and out intermittently and the left hand fan doesn't come on at all....

A/C still works however!!

The relays are in the front of the fan surround behind the inner grill....two green ones, one on each side and one black one slightly lower in the middle....I can't work out how to attach a pic.