Cooling Fan Coming on Late, I Think? Topic is solved

[esl_97_850_T5]

volvo850diag has a ECU 51 (ie, COMBI Instrument Panel) "Test Gauges" function which (among other things) wll cause the Temp Gauge needle to swing thru much of its range of motion. If you do that "Test Gauges" check, please tell us exactly how far down the needle swings in relation to the red mark at the bottom of the Temp gauge and how far up the needle swings in relation to the red zone at the top of the Temp gauge.

I'd suggest doing it several times to see if the behavior is always consistent.

[rspi]

Hmmm, Not sure what is going on there. Maybe a bad gauge, I have had to replace one of them.

[sleddriver]

If the low speed connector comes off its pin on fan relay then the high speed fan will be triggered at a higher temp. The plastic on those "bullet" style connectors disintegrates and the grey plastic connector body can't keep them on. Easy to inspect. Look just under that top fan shroud plastic bar for the big rectangular relay and see if the grey plastic two wire connector has a loose wire. If it is loose then push it back up on the pin on relay.

Just experienced this and made a new post about it. I didn't even know the fan HAD two speeds. So the low speed connector must have come off as my fan speed suddenly jumped up. When I touched the relay, it would quickly rise/fall/rise/fall....

Obviously I have another 'bullet' connector/housing/contact to fix like the ECT I did last year.