cam99

Vacuum Pump Installation - where to get switched power

I'm installing a vacuum pump but don't know the best place to get switched power. Has anyone wired one before and what did you do? If the fuse block which fuse?

I bought the pump years ago and its installed in the wheel well, not sure of it power draw. I need to determine that first.

Does anyone have wiring schematics for the C3?

DUB

What years is your car??? Fuse panels changed and also did the type of fuse used.

There is a reason for needing to know this???

I guess the vacuum pump requires some value of fuse...???

Reason for asking this also..

Are you setting it up to run all the time or setting it up so it runs when a trigger switch or sensor is used????

DUB

caryb78

Both the pumps I have purchased want a circuit off of a 30 amp fuse. You can pick it up off of the fuse block spare with a wire with a bayonet connecter and splice in a 30 amp fuse. Pump will be on when ignition switch is on. You can also splice in a toggle switch to tun the pump on/off

cam99

Thanks, btw its a 1977. This is how I wanted it no extra switch just off the ignition switch,

gjohnson

Wiper motor is switched power. I have my elec. choke tapped there.

DUB

That is NOT how it works.....because....the terminal you are plugging into at the fuse panel is ALREADY protected by a fuse that I am sure is LESS amp rated than what you need.

I know people can wire things as they want for ease of installation...but IF the fuse that is protecting that terminal in the middle of your fuse panel is 10 amp or 20 amp....then guess what you vacuum pump is being protected at. it is being protected at the rating of THAT fuse.

And thinking that you can go in and put a 30 amp fuse in place of THAT fuse. just understand that the fuse is NOT there to protect the component that it is supplying power to....it is protecting the WIRE.

The last question in POST#2 was asked for a reason and IF you have the vacuum pump to run all the time on that terminal in the middle of your fuse panel. Keep in mind that whatever fuse is beside the terminal and protecting it.....when it ALSO is being used...THAT fuse in the fuse panel can blow.

Do as you wish and I hope all goes well.

DUB

gjohnson

DUB knows his sh4t!!

DUB

Thanks.

Not knowing much at all about the gauge of the wiring for the vacuum pump that is being installed. And IF that wiring may also need to have larger gauge wire used due to it is powering up a motor. I just hope the person installing it takes into consideration factors that can lead to a problem IF the system is not wired correctly.

DUB

tviscomi

Got a pic of where/how you install your vacuum pump? I about to install a Summit pump and having trouble finding a good location on my 1978

caryb78

I cant get pics right now since car is in transmission shop.Pump installs in compartment just behind driver side wheel well. Mount to wheel well side. Be sure to use large area washers on BOTH sides of the mount bolts. The pump has 2 wires one is power wire one is ground. The ground is easily picked up off the frame just in the lower rear of the compartment. The power wire is the heavier gage wire. BE SURE TO USE THE SAME GAGE WIRE OR MORE FOR THE POWER WIRE. SAME FOR THE GROUND. I elected to use a push/pull switch mounted on the panel under the steering wheel that has the headlight vacuum switch mounted on it. Thats also the easiest place to pick up a vacuum gage connection.If you have a service manual go to the wiring diagrams and find the fuse panel layout. It should show you where there are spare locations on the panel. You can use one of those for power but it wont necessarily be switched and it may already be used. You can pick off of a spare connector but as Dub said it may already be protected by a lesser rated fuse. Since you must protect the entire circuit the fuse must be installed as close to the power source as possible to protect the entire wire run. You can install a lower rated fuse which will blow at less than 30 amps but will provide added protection if you are unsure. I have not seen this pump draw anywhere near 30amps which is a lot. I will post pics when car returns. Good Luck

Sunracer

Might this be a case where you want to use a relay and power source separate from the fuse box and just use power from the fuse box to trigger the relay?