lLow coolant light and glow plugs

[Bill Moncrief]

Hello;
I have two questions concerning a 6.2 in 1985 K3500. When starting truck sometimes glowplug lite will not come on and plugs won't heat if you shake wire harness on driver side fenderwell it will usually go ahead and work can't find any lose connections or arc marks. Both radiator and overflow tank are full to proper level and stay that way but low coolant lite stays on. Bad sensor maybe? Truck does not belong to me but any help would be apreciated.
Thanks
TOWER JAKE

[bmiszuk]

Low coolant sensor on my 83 is located on the passenger side of the radiator, about halfway up above the lower radiator hose. If the wire is disconnected or cut the light goes on. You might check the wiring, or perhaps the sensor is bad.

[waorth]

From time to time I've to clean all the small contacts on the coolant switch/sensor with abrasive paper to stop the low coolant light coming on.

As for the glow cycle problem, try searching the forum.
Keywords:
glow plug relay
glow controller
glow plug

Regards,
Walter

[BobND]

The low coolant light circuit and the glow plug circuit pass through a common connector body in the area where you've been wiggling the wires. I would try unplugging the connector, spraying some electrical contact cleaner on the connections, and plug and unplug it a few times to polish up the pins a bit.

The harness from the connector mentioned previously goes to the large bulkhead connector just above the driver's left foot. If needed, you could unbolt that large plug, and clean it's terminals, too.

Also, check ALL engine, battery, and body grounds.