Paging Mindwipe... Paging Mindwipe

Greetings...
I'm desparately trying to find the Coolant Temperature Control Unit
(possibly Bitron?) on my Pug 306 Meridian 1.6.
Some reports suggest it should be in the closed area under the left
headlight (near the horn), but I don't seem to be able to find it there.
My radiator fans don't run when they should and I have eliminated most other
things.

Any advice much appreciated.

- Steve

 

Greetings !
Thanks for getting back.. I've been away a couple of days.
Yes, it does have air con, and 2 fans. But the setup of the control seems
different to many earlier 306s.
It appears that it probably doesn't have a Bitron fan control unit at all
(see thread between myself and Nigel starting 3/2/04)
It's looking like the main ECU does than fan control on this late TU5
engine. I'm just praying it might be one of the sensors as opposed to the
ECU.
Luckily I have access to an identical friend's car tomorrow, so I'm going to
measure the sensor resistance on his and compare it to mine.
Any other ideas really most welcome...

Cheers,

- Steve

 

if it is the one with a bitron unit then you can force it into self test by
disconnecting the brown temp sensor(if its not there then the bitron isn't
either)
in self test(ignition on) the fans will kick in at slow speed then fast
if its not got this then it has what pug call FRIC where the fan is
controlled inside the engine control unti
i have never had these go faulty there is usually a resistor behind the
grille (bottom) when it has this system,i have had to replace the resistors
b4 but usually on 406's
lmk how you get on

 

Hi Jeff,
No, as far as I can tell it has not Bitron unit, but it does definitely have
3 relays and I can't find any resistors. I can only assume that the ECU
controls the 2 relays directly ?
There are 2 sensors near the thermostat housing, both with blue connectors.
One of them has 3 wires and appears to have 2 thermistors in it. Nigel
suggested that this was probably the sensor to the ECU. I compared it to a
similar car today, and the resistances seemed similar-ish.
Nigel suggested that the second sensor probably feeds the dashboard
indicator, and I've not investigated that one yet.
The car announced "STOP" again today in traffic - It was indicating around
95C at the time. I popped on the air con and it slowly cooled down again.
I'm not sure what to try next. I shall probably check the earth bonding of
the fan circuits, but I don't really suspect that.
I'm tempted to try disconnecting the 3 wire sensor (with ignition ON) and
see if that makes the fans come on ?

Many thanks for your help,

- Steve

 

check the connector at the ns of the radiator,these tend to suffer a lot on
theses cars and somtimes melt
you may need to remove the front bumper. if its this connector i usually
just cut it off,solder and seal
then inspect the wiring behind the bumper this usually corrodes away at the
ns near the horn(you can usually see the green sulphation in this case)

 

Hiya Jeff,
I did take a very good look at that connector. I unplugged the loom and the
pins looked bright and shiny. Nevertheless, I gave it a squirt of switch
cleaner and re-mated it a few times for good measure. I'm guessing that it's
probably OK because the fans do come on slow when the air con is ON?
I was in traffic yesterday so I deliberately let the car warm up to check
the (indicated) temperature when the STOP light came on. This was only 95C
(indicated). Seems a bit low ?
I also unplugged the (dual?) sensor with 3 wires and compared it's
resistances with an identical car. The resistances at 10C and 70C seemed
similar, so I'm presuming that sensor is probably OK.
Today I tried to test the second sensor which has one wire. I had to take
the inlet air "ducting" off to get access to it. Unfortunately the blue
connector seemed "locked" in place and I wasn't sure how to free it
connnector without breaking. I'd really like to be able to test it because
once again I can compare it with a similar car. Any advice ?

Thanks again for your support Jeff.

- Steve

 

connector is usually of squeeze type but can get stuck lube it up and leave
to soak in