Air Cleaner Cab Indicator won't shot off

[BigJohn]

I have a 318D with 400hrs on machine. When I was operating today on a very rainy day and My air flow indicator in the cab came on. I shut the machine down and replaced both filters (primary and Seconday ). I went back to operate again and the indicator light came back on again. On that system it has a (Pressure switch) and a (Thermoucoupler air temp sensor) Would anyone have an idea what would be the problem? Is it possible that I have a bad sensor or switch? HELP

 

[BigJohn]

That indicator light is known as ( Engine Air Filter Restriction Indicator)

 

[BigJohn]

That indicator light is known as ( Engine Air Filter Restriction Indicator)

When I disconnected the ( Air Temp Sensor ) the light still stayed on but when I disconnected the( Pressure Swith ) the light went off.

 

[Tazza]

When I disconnected the ( Air Temp Sensor ) the light still stayed on but when I disconnected the( Pressure Swith ) the light went off.

Some of those restriction switches need to be pressed to reset, could yours be the same? It should be attached to the back of the air filter box with wires going into it.

 

[BigJohn]

Some of those restriction switches need to be pressed to reset, could yours be the same? It should be attached to the back of the air filter box with wires going into it.

your right Tazza. I took the switch off and you see a clear blubble on the top. I pushed on it a couple a times and banged it around on the bench, Installed it again and ran the machine for awhile and no more light. The switch still works because the continuity test showed ok. Thanks, Tazza

 

[Tazza]

your right Tazza. I took the switch off and you see a clear blubble on the top. I pushed on it a couple a times and banged it around on the bench, Installed it again and ran the machine for awhile and no more light. The switch still works because the continuity test showed ok. Thanks, Tazza

Glad it was an easy one. My 743 had the type that you needed to press a button to reset it, but had no electrical switch.
If yours fails, remember that you can get them from truck supply shops, they are used on a lot of trucks, you just need to get them to match the value for vaccum that they operate at.