MD22 engine temperature switch

[Peter]

Got to change engine water temp sensor as failed. But when looking at engine and wiring diagram/manual noticed a engine water temp switch sensor. So some questions. What does the water temp switch do? Manual is a bit vague on function. Which sensor is it? Both by thermostat, one horizontal, one vertical. Before I remove and order new, thread size
Thanks Peter

 

[Yngmar]

The engine has senders for both alarm lamps (which are on/off, thus labeled "switch") and gauges (which have a range and are labeled "sensor"). Some are both in one (three connectors), but the water temperature has separate ones. Depending on which control panel you have, the water temperature sensor is going nowhere in the engine loom, only if you have a temperature gauge it's connected. So if you have the simple panel and a faulty alarm, it's the "switch" type you need to look at. If you have a gauge that reads wrong but no false alarm, it's the "sensor" one. Or the gauge

Volvo Penta Exploded view / schematic Thermostat housing MD22L-B, MD22P-B, TMD22-B, TMD22P-C, TAMD22P-B - MarinePartsEurope.com

 

[VicS]

The engine has senders for both alarm lamps (which are on/off, thus labeled "switch") and gauges (which have a range and are labeled "sensor"). Some are both in one (three connectors), but the water temperature has separate ones. Depending on which control panel you have, the water temperature sensor is going nowhere in the engine loom, only if you have a temperature gauge it's connected. So if you have the simple panel and a faulty alarm, it's the "switch" type you need to look at. If you have a gauge that reads wrong but no false alarm, it's the "sensor" one. Or the gauge

Volvo Penta Exploded view / schematic Thermostat housing MD22L-B, MD22P-B, TMD22-B, TMD22P-C, TAMD22P-B - MarinePartsEurope.com

But they are called "sensor" and "thermo monitor" in the parts list. Volvo Penta Exploded view / schematic Electrical System MD22A, MD22A-A, MD22L-A, TMD22A, TMD22-A, MD22L - MarinePartsEurope.com

If you look at the wiring diagram in the owners manual you will see that the sender for the gauge ( when fitted) has a light brown wire on it, whereas the sender for the warning light has a brown/ white wire on it