Radiator Fans constantly on - 88 Supercharger with Air Con

[emrrtwo]

Recently had a new radiator fitted and since then the fans run all the time even at the first click of the ignition without the engine running. From reading on-line I think its went into a safety mode as something is wrong.
Did various searches and so far myself and the garage have tried the following but still no luck

Cleaned up all the connections
Tried 2 different Temp sensors on side of radiator
Tested Fan & Air con relays in frunk with multimeter as per bgb
Tested Air Con pressure switch
Replaced Fan & Air con relays from previous mk1
Replaced Fan control relay / ecu in boot with that of previous mk1

We are both running out of other things to try, anything we have missed or any other suggestions?

Cheers

Kieran

[kaiowas]

The fan will be on all of the time if the temperature sender/switch that is screwed into the radiator is not connected (I'll often unplug mine if I need to cool the car down after a run on track - one day I might get around to wiring in a switch!). As you've swapped the rad (and therefore disturbed this area) it's the first place i'd look. As you've already tried fitting another sensor the next thing i'd probably do is check the wiring to it in case you've broken a wire during the swap.