Temp Gauge Sensor

Gammy leg · Post by **Gammy leg** » 26 Jul 2007, 17:15

Chaps,

Any idea where I might find the Temperature Gauge Sensor on the engine of my 1.9TD Synergie? I think it has been knocked somehow and the gauge now does not function. When I switch on the ignition and wait for the pre-heat light to go off, the temp gauge rises to max then drops to min 3 times then seems to switch off completely. I can't find my Russek BOB to check location of sensor.

Thanks

Gammy

Post by **CitroJim** » 26 Jul 2007, 17:31

Hi Gammy,

On the thermostat housing adjacent to the fuel filter. There may be three similar looking ones lurking there. One will be the gauge sender, the other will be for the temperature warning light and a third (if you have aircon) will be the Bitron Sender and will be brown. I think the gauge sender is blue but I'm not sure. The warning light sender will only have one wire despite having a two-way connector on it.

Check the connections first. They suffer from crrrosion due to stray drops of coolant.

Gammy leg · Post by **Gammy leg** » 28 Jul 2007, 13:31

Jim,

Thanks for the reply. I found all three connectors, 1 blue, 1 green & 1 brown. I disconnected all 3 individually but problem still persists. Removing Brown connector started cooling fans, but removal of Green & Blue had no effect at all, the temp gauge still went through the same 3min-3max-off routine even with connectors disconnected. It is almost as though it has cross-wired itself to the ABS self-check system or similar.
This started after the fuel filter was changed as part of tank draining exercise posted elswhere. I can't see any evidence of damaged wiring or fluid leakage around the filter housing either.

????????

Gammy

Post by **CitroJim** » 28 Jul 2007, 13:45

The gauge sender (as well as the coolant over-temperature light) is the blue one. The brown one is the Bitron and it is correct that disconnecting it will spin up the fans. The green one on a diesel is the coolant temperature sensor/cold advance sensor depending on wether you have mechanical or semi-electronic injection.

I'm researching this as I have the same problem as you, although mine is very intermittent. Mine will go for weeks behaving itself and then have a day of playing the most amazing tricks. It either reads zero, or reads very high and wavers all over the place from hot to cold and anywhere in between.

It may be a dodgy earth as mine generally reads high when it is working and is influenced by turning on the lights and/or air con

It is quite scary to put the headlamps on as see the temperature immdeiately shoot up 10 degrees

I'm going to have to pull the instrument pod out sooner or later and have a look.

In the meantime, do the old time honoured test of disconnecting the sensor and looking at the gauge. It should read zero. Now earth the gauge sender wire and it should read full-scale (i.e. very hot). The gauge wire, if I remember correctly is no. 401. I'll confirm as soon as I get home later today.

I want to do this test myself but the sensors on the Activa engine are just about totally inaccessible

Just like most things on the Activa!!!

Post by **CitroJim** » 28 Jul 2007, 14:34

Gammy,

It is wire 401 from the blue sensor for the gauge. Wire 405 operates the over-temperature light.

Another test you can do to prove if it is the gauge or sensor is to put an ohmmeter between the sensor (with wire 401 disconnected) and earth. You should see a steady resistance that falls as the engine temperature increases.

Gammy leg · Post by **Gammy leg** » 28 Jul 2007, 23:37

Jim,

Thanks for the additional wiring info. Don't quite understand how the gauge and warning light still work even when the connectors are disconnected though??. Any suggestions.?

Another problem appeared yesterday regarding the indicators. Could be linked to the gauge issue but probably just a red-herring. Switched on indicator to turn, turned, indicator self-cancelled but relay continued to 'tick-tick' only at double speed as if one of the bulbs had blown. Checked outside whilst this was going on, but no lights flashing either front or back. Happened on both right and left indicator initially and then started at random even when not indicating....... God I hate cars - particularly the electrical bits.

Gammy

Post by **admiral51** » 29 Jul 2007, 12:15

not too sure about your temp gauge problem but try this for your ticking/indicator problems
http://www.frenchcarforum.co.uk/forum/v ... highlight=

sure ive read somewhere on here something to do with the hazard lights and or cleaning indicator slalk switch that solves this problem

colin

Post by **admiral51** » 29 Jul 2007, 14:35

think this is the link for the post about the indicators

http://www.frenchcarforum.co.uk/forum/v ... ht=#143747

colin

Gammy leg · Post by **Gammy leg** » 29 Jul 2007, 17:46

Thanks Colin. At least this seems to be a relatively common problem and does not appear to be connected to my gauge issues..

Gammy

Post by **admiral51** » 29 Jul 2007, 18:49

gammy
not sure if your car has a/c if so then the temp sensor is done through the bitron unit.
its in here somewhere

http://www.frenchcarforum.co.uk/forum/v ... ht=#145523

colin

Gammy leg · Post by **Gammy leg** » 30 Jul 2007, 12:42

Thanks Colin, I shall investigate this evening.

Gammy

Gammy leg · Post by **Gammy leg** » 30 Jul 2007, 20:30

Chaps,

Had a look this evening but don't really know what I'm looking for. Can anyone give me an idea what the Bitron looks like, size , colour, shape etc. I have a feeling as with other models it may be lurking round the nearside front headlamp unit or below the battery box.

Thanks

Gammy

Post by **admiral51** » 30 Jul 2007, 20:48

gammy
the bitron is about the size of a fag packet and mine was bolted underneath the n/s headlight

cant remember if i needed bumper off to get at it but i found it whilst i was replaceing fan housing and had bumper off

click on this link click on album and you should find 3 pics of bitron locations and pics of pins etc courtesy of Clogzz

http://s132.photobucket.com/albums/q23/ ... socket.jpg

colin

a large fag packet sorry

Gammy leg · Post by **Gammy leg** » 31 Jul 2007, 11:32

Colin,

Thanks for the tip ( filter

) and link to Cloggz photos. I think I may have spotted the Bitron last night either under battery box or maybe attached to ECU housing on O/S inner wing. Could not see under N/S headlight though, too much other junk seems to be buried there, but will investigate further.

Thanks again

Gammy

Gammy leg · Post by **Gammy leg** » 01 Sep 2007, 23:52

Just back from my 2 week holiday in France. Almost 1500 trouble-free miles. The temp gauge is now miraculously fixed and this is how i done it.

1. Stupidly left one of the interior lights on for a couple of days which partially flattened the battery.
2 Tried to start the car and listened to a cacophony of chatter from 1/2 doz relays attempting to energize - incl. the Bitron.
3. Borrowed set of jump leads from friendly camp site owner and jump started from a Mazda 6 ( nice motor )
4. VOILA! car started on 1st turn and amazingly temp gauge was back working again.

This may be a new way of unsticking sticky relays!!

Regards

Gammy.

ps. Lost the radio code during all this but that is also sorted, details elsewhere