Coolant and screenwash lights intermittently on and off.

[Custador]

A little background: My old battery died and was setting my alarm off overnight, so I disconnected the earth lead... And then discovered the boot lock is seized and would not open without power. So, powered up through a boost point under the bonnet (up by the washer reservoir on the passenger side). Popped the boot, replaced the battery, all tested and working nicely, alternator chucking out good voltage, happy days.

Until later. Dual carriageway drive, came to stop-start traffic, the coolant and screenwash warning lights came on for a few seconds. And on. And off. And on. And off. Etcetera etcetera. Fluid levels are fine in both tank, fuses and relays all intact, puzzlement is the rule of the day.

I don't have a code reader, by the way.

 

[Grahamcol]

I understand the coolant and screenwash sensors are wired in such a way that either of them can flag up either warning light. I'd check the wiring / plug to each sensor and then maybe you will need to look at the sensors themselves.

 

[Custador]

Aha. Thanks for that; I think my coolant pump is squeaking, so I wonder if the fluid has dropped to marginal levels and the sensor's triggering both... Will let you know.

 

[Custador]

You were correct. Topping the coolant off an extra 1cm solved it. One sensor triggering two lights.

 

[Custador]

A recap on this: The problem came back and became permanent - I now have both warning lights on at all times. Fluid levels are fine in both tanks, and I have replaced both sensors with no effect. Fuses are all intact.

HELP!