405 rad cooling fan

[reades]

Hi,
Pug 405, 1.9 GLD diesel estate, 1991 H reg, 176k miles, non Air con.
My rad fans don't come on in hot weather. I've never waited for it to overheat, if the temp gauge creeps up I open the windows and turn the heater and fan on, which brings it down. (Annoys the kids always good for a laugh!).
Unplugged the rad sender. There are 3 wires. Shorted 1 & 2 and the fan (or fans, not sure) came on. Shorting other pins made no difference. Question, do I have a rad switch problem or relay problem? I don't want to spend lots on this car, what would be a cheap work around?
Searched this forum I came across some useful stuff and have found the relays are near the fans.
In trying to get to the bottom of this I came across a second possible problem. One of the 3 green relays mounted on the fuse board is really hot. I swapped them around and the same one gets hot. Sounds like I need to replace the relay. Anyways how do I find which relay does what? If I just unplug the suspect one will I do any harm? haynes manual doesn't help at all on this.
Thanks in anticipation.
Rod

[solara]

Sounds very much like a faulty rad fan switch. When you manually bypass the rad fan it works (shorting pins 1&2), so thats pretty much conclusive.
Have a replacement ready, and do a quick swap without losing too much water. Should be a quick fix.