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Heater Boost Pump

Yahoo Message Number: 86484
I had a minor coolant leak at the hose clamps connecting the heater boost pump to the heater hose going to the front OTR heater.
I fixed that then wondered how the pump is controlled. I turned the ignition on - pump did not run. Then I put the heater in heat position -pump did not run.
Does anyone know how the heater boost pump is controlled? It is located on the driver side just behind the rear axle. It is mounted vertically with input and out pipes parrallel and pointing up. The motor is under the pump.

George Harper
04 Allure 31093

Re: Heater Boost Pump

Reply #1 –
Yahoo Message Number: 86492
I do not know, but guess it is run by the ignition switch. I have removed the rear pump and its related gate valve, but still have one mounted behind the passenger bumper.
Your pump may have given up. My rear one dumped coolant on the highway twice and caused the engine to shut down.

Dean

95 Magna 5280

Re: Heater Boost Pump

Reply #2 –
Yahoo Message Number: 86499
George,

I suggest that you run separate 12VDC wires to the pump and determine if it works or not. Otherwise you can turn on the ignition and probe the wires for power.

George in Birmingham
'03 Magna 6298
George in Birmingham
2003 Magna 6298

Re: Heater Boost Pump

Reply #3 –
Yahoo Message Number: 86505
I don't know on the 04 but on my 97 Allure the pump runs anytime the ignition is on. I don't have my wiring diagrams at home , but there is a fuse in the circuit. In my coach it is by the drivers left leg under the dash. I believe there are other items on the fuse for the pump. My coach only had one pump mounted where you indicated on the frame rail in the engine compartment.. I blew the hose downstream of the pump last year and overheated losing about 4 gallons of coolant. After that I installed a couple of ball valves where the heater hose comes out of the engine and installed silicone hoses. I also bypassed the pump and removed the power wire. As I live in AZ heat to the dash is not to big an issue, I still get heat without the pump, but it come on slower.

Hope this helps

Jack Allure40 30076

Re: Heater Boost Pump

Reply #4 –
Yahoo Message Number: 86520
Jack, George, thanks for the reply.
I think I will study the wiring diagram and see if I can find the pump and how it is controlled. I can then check the fuse. It sounds like it should be on anytime the ignition is activated. Mine does not turn on with the ignition. Nonetheless, I have plenty of heat out of the OTR heater. The heat control valves are of poor design, though, because the heat is either on or off even though there is plenty of graduation in the control.
When our coaches get some age on them rubber hose deterioration is a problem. My pump has two NAPA connector hoses connecting with the heater hose line, but they feel OK.

George Harper
04 Allure 31093