That flashing red coolant level light again!

[Reg the Wedge]

Hi all

I hope that someone can help, because I don’t know where to go from here.

The flashing low coolant level light is on all the time. As soon as I turn on the ignition the light starts flashing and doesn’t go out. I’ve read all the archive posts and the Wiki section too, but I’ve come to a full stop.

I changed the sender unit in the expansion tank and the relay 43 before reading the Wiki. I’ve removed the relay 43 and turned on the ignition, but still it flashes. According to the Wiki, this means that the fault is not on the coolant level part of the circuit, but what’s left? The temperature gauge works correctly, so there can’t be a problem there. I’ve cleaned every earth that I can find, including the crown behind the fuse box.

Any thoughts, guesses or new swear words would be welcome. Oh yeah, it’s a 1600 diesel non turbo

Cheers all, Lawrie

[AngeloEvs]

If the LED continues to flash with the Module 43 removed then the fault may be with the gauge. Does the temp gauge read cold when starting up?

If it does, then it sounds like the problem is with the temp gauge itself as it contains a microchip that controls the LED self test period and the triggering of the LED via Module 43. Check the nuts at the rear of the gauge that secure it to the membarne PCB as these are also the gauges connections. The small center one at the rear of the gauge is the earth for the microchip and, if loose or has a poor connection, will cause flashing red LED syndrome (as will a poor earth from the dash multipin connector).

Remove the module 43 while carrying out any investigative work to isolate the level sender and it's ability to interact with the temp gauge microchip.