the difference in the wiring is that the syncro temp sensor for the gauge uses the sender body and the thermostat housing and thus the engine as the earth contact so just has asingle wire in the loom (yellow/red), whereas the 2wd plastic tstat housing has no conductivity so requires a 2pin sender and has an earth wire in the loom for it (brown)
as it's a resistive change a poor earth or positive connection will give a poor gauge
Metal thermostat housing temp sender.
Moderators: User administrators, Moderators