Overheating in traffic on 1990 Mazda Miata MX-5

Overheating in traffic, Fan is not coming on. A/C fan does work. Tested fan itself and works whem power put onto terminals, Can find no fuses blown. Shorting the temp sensor on the thermostat housing to earth I can hear a relay kicking in at the fuse box. have swopped that relay with one the same - problem remains - any ideas please?

Asked by for the 1990 Mazda Miata MX-5
2 answers
replace thermostat
Same happened to me, fans weren't turning on even after i got new fan motor's. The thermostat sensor wasn't connecting with the thermostat properly... so i got a plastic tie and adjusted the thermostat sensor in a position that made contact and therefore activating the fans (definitely ghetto rigged)