Foretravel Owners' Forum For owners and Fans of Foretravel Motorcoaches September 08, 2025 ...

95 u280 Grandvilla mystery pump

February 11, 2022, 01:24:40 pm

Hello,  I can't seem to find any info on what this pump/motor does.  It is mounted in front of the firewall in the u280 grand villa.

There are some small rubber lines running to what looks like an accumulator that is spherical in shape.  The power wire is unplugged but the unit works ( I powered it up with a battery and jumper wires)

There is a diaphragm looking device that has wires coming from it and a spare spade that looks like this wire should connect here.

I do not want to connect it and have it be in the e wrong place or perhaps the previous owner disconnected it for a reason. 

Thanks for the help

Quote Selected

Re: 95 u280 Grandvilla mystery pump

Reply #1 – February 11, 2022, 01:29:15 pm

That is the vacuum pump.  It supplies vacuum to power the air doors in the dash heating/air conditioning system.  The round globe is a vacuum reservoir.  The brass disc is a vacuum switch that turns power to the pump on and off.

See threads linked below for more info:

Help identifying what this is for - Air pump

Vacuum pump, what is it?

Quote Selected

Re: 95 u280 Grandvilla mystery pump

Reply #2 – February 11, 2022, 02:26:10 pm

If the vacuum system is not working or disconnected, the classic symptom is the dash heater will only blow through the defrost vents. I replaced the vacuum pump on my '91 U300 and the vent control slider controlled the heater vents again.

In Dash HVAC Duct Selector Kaput
 

Quote Selected

Re: 95 u280 Grandvilla mystery pump

Reply #3 – February 11, 2022, 06:58:46 pm

Most any kind of 12V vacuum pump will fill the bill. Cheap on ebay. Put a plastic stop on the heater/AC control so it won't slide all the way to the left. Stop should block the last 1/4" and you won't have any more vacuum pump failures. If it goes all the way to the left, the pump will run most of the time.

Pierce

Quote Selected

Re: 95 u280 Grandvilla mystery pump

Reply #4 – February 14, 2022, 04:08:09 pm

I plugged it in but I am not getting power to the vacuum pump.  The fuse is good but I can't get it to turn on

Quote Selected

Re: 95 u280 Grandvilla mystery pump

Reply #5 – February 14, 2022, 04:11:03 pm

Check the relay next to the vacuum switch.

Quote Selected

Re: 95 u280 Grandvilla mystery pump

Reply #6 – February 14, 2022, 04:44:37 pm

What Brett said. 

Quote Selected

Re: 95 u280 Grandvilla mystery pump

Reply #7 – February 14, 2022, 05:00:38 pm

Thank you everyone

The problem ended up being the power wire to the pump was mistakenly hooked up to the little air solenoid instead of to the relay.  It is working as intended now

Thank you again, everyone's input really helped

Quote Selected