coolant light came on, engine not overheating

[xpress]

hi there.

on a short run, the van coolant light came on, the engine had only been started, the needle was barely coming up to the start of the coolant light, stopped, checked with my hand the engine wasn't even warm. i put about a small water bottle of coolant in the tank near the flap. haven't checked the main left hand tank yet. went a few miles on and needle was fine. On the way back, the light started blinking again, constantly, i put the heater on full heat and on, and then i opened the throttle to full instead of my very gentle acceleration i normally do, and then it dissapeared and stayed off. needle was still the good side of the led, never went over it. i thought that there may be a switch fault, or water pump not circulating properly, but there may have been a bit of air in there and i might have pushed it out. after the journey back, the engine was still not excessively warm to indicate any overheating due to lack of coolant circulation, blockage or coolant loss.
any thoughts? cheers.

[Sh!tbucket]

I'd check the level of coolant in the main tank.

If it get's low, there's a switch in there that turns on the blinky LED.

I think the left tank should always be full.

[xpress]

ah that makes sense. main tank must be getting low and expansion tank hasn't fed it yet. i will check that. good plan. will report back!

[Hacksawbob]

there's a switch

actually a two pronged sensor in header tank, it could need a clean or replace . Also theres some electricery in the dash that handles the coolant sensing could have gone bad, or the multi pin connector under the dash could be loose/corroded. or the wiring to the sensor could be corroded /broken/damaged

[xpress]

thank you all. update, no more lighting of the coolant light, coolant is topped up and kept an eye on. cheers.