Can Or Do Water Temp Sensors Switch Relays Over?

[pugpete1108 62 1 Cars]

Im looking for a quick solution to my failed fans on my 306, and was wondering if a correctly rated temp switch fitted in place of the bitron sensor in the thermostat housing switching a relay direct to the fan itself (currently have a dash switch but have to keep an eye on temp) as a temp measure?

 

just an idea?/

[welshpug 1,666]

you mean like a Rallye has? though the sensor is in the rad on those.

 

though that wont really do much if its the fans that are buggered anyway

 

it'll be just as much time spent faffing a temp bodge as it would be to fix it properly tbh!!

[pugpete1108 62 1 Cars]

the 306 has a really overcomplicated fan system (bitron ecu unit) . my fans work fine when bridged to bypass the 3 relays system it has (i couldnt even get either fan to work through these relays, thats with bypassing the ecu unit) on a switch on the dash.its something else that has gone wrong??

 

i have a couple of spare temp sensors lying around which i could use if they were capable of switching the 12v supply needed to operate a relay. and as i have all the wiring there (just going to the switch instead) it wont be a hard job to do as a quick fix.

 

im hoping its just the bitron ecu but i havent got the time or effort required to fix it at the mo, the ecu is up in the wheelarch and i will need to remove the front end again the rewire the fans to the original system.

 

really just need something to remove the human error (me) when it comes to switching the fan on when it gets hot.

[Anthony 1,003]

Most (if not all) 306 radiators have a hole for a 205 style thermoswitch, as that's what the non-AC models use. Fit a thermoswitch, and then as a temp measure you can run the wires to that instead of (or in addition to) your dash switch, thus switching the fan on automatically when it gets hot.

[pugpete1108 62 1 Cars]

good call, i have just been looking at those types of switches (similar to the 205 in rad one) and wondered if the 306 had a bung for one.

 

would a a/c model rad have a hole? as thats what i have.

 

i'll double check tomorrow, what temp does a 205 thermoswitch kick in?

[Anthony 1,003]

Usually there's a bung covering it, but both of the 306 GTi-6 radiators in my garage have the required hole.

 

Switching temperature depends on the individual switch, as there's several different temperature ratings of them.

 

The purple banded ones are 92/97 whereas the red and yellow are both a few degrees hotter (97/102 rings a bell for one of them). That's slow/fast speed, but you can easily wire it to the slow side for a lower switching temperature (indeed, that's what I usually do regardless so the fans come on full speed straight away)