'thermofan' not working

[Supra Sarah MK3]

the small thermofan on the left hand side of the radiator isnt working...hence major contributor to overheating

the connections mite be loose or something.. where does it connect to...undeneath the fuse box where its hard to get to i think

we connected some wires to it and it does work

does it come on all the time when engine is on? or??

how would u fix the prob?

i heard that it is called air conditioning fan..??

thanks for any help and comments

 

[Supra Sarah MK3]

Air con low gas safety switch was the problem. It had an Open circuit, as if there was no gas in the system. But there is plenty of gas as the glass eye on the dryer receiver bottle indicated.

We bypassed the switch by looping a piece of wire between the two terminals in the plug. The swith now doesn’t intervene when the is low gas, but common sense dictates when the air con doesn’t get cold or cycle.

now the thermofan works when the air con is on. do u think that this will have a bad effect on the car/engine??


unforunately its not on all the time when the engine is running

 

[cuel]

That fan is for the a/c, as you found when you rewired it. If you're using the a/c, and that fan isn't working, it will make the car run hot. If it's overheating without the a/c on, you have other issues to fix.

 

[jetjock]

A bit more detail if I may:

The "low gas switch" isn't. Just the opposite. It's a high pressure switch that closes and operates the fan whenever the high side of the refrigerant system exceeds 220 psi. Such a high head pressure happens with insufficient airflow through the condenser such as in stop and go traffic on a hot day. The fan also operates when coolant temperature is more than 100 C.

The actual low gas switch (low pressure cutout) is part of the dual pressure switch and is independent of the switch you're talking about. It opens at 30 psi to avoid compressor damage from lack of oil caused by insufficient refrigerant and also at 380 psi. That would happen if the expansion valve failed closed or some other restriction was present in the high side of the system. In both cases power to the compressor clutch is removed.