wiring my compressors

[62scraper]

I want to wire two compressors with a pressure switch and a toggle switch in the cab so that I can turn them off when I am not driving the truck. Do I run a wire from the battery to a ciruit breaker and then run a wire to each compressor and then run a wire to a toggle and then to the pressure switch and then to the circuit breaker? Are relays and circuit breakers the same thing? Should I put a fuse somewhere and what size? Should the power to the toggle come from a source that is constant or only when the ignition is on? I want to do this right the first time and any help is greatly appreciated.

[Slmd92DIME]

Run a small wire with a inline fuse from anything that uses ignition (wipers, radio) to the toggle, on the other side of the toggle run it to one of the PS prongs, then the other side of the PS run it to the relay also. I usually use one large car amp wire to a distribution block then from the block to each relay. You will need 2 4 prong relays.. One will be ground, small power (from toggle), big power, and your red wire out of your compressor. Here is a diagram from SD http://*****************/how_to/wire-...compressor.gif

I hope that helps if not let me know if you need anything

[62scraper]

That does help, thanks. Is a dist. block the same as a circuit breaker? Here is a picture of what I have.

are you talking about something different? What size fuse should I run between the PS and the relays? or do I need any fuses anywhere?

[ChiefRocka]

The one you listed is the self-grounding solenoid.

If you had the other type (terminal ground), then you could just ground one side of your toggle to the dash, then run the other terminal to the solenoid.

This acts as a 'ground' interrupt, and is much easier to wire.

You will have constant power at your 'noid already....therefore you just interrupt the ground to the press. switch.

[62scraper]

Originally Posted by ChiefRocka

The one you listed is the self-grounding solenoid.

If you had the other type (terminal ground), then you could just ground one side of your toggle to the dash, then run the other terminal to the solenoid.

This acts as a 'ground' interrupt, and is much easier to wire.

You will have constant power at your 'noid already....therefore you just interrupt the ground to the press. switch.

The pressure switch has two tabs. I thought that pos had to be connected to the switch but I could put ground to each side? So I should run a ground from the dash to toggle to PS to relays?

[62scraper]

Should I use one like this?

[ChiefRocka]

You can wire it as shown.

The red lines on the right come from the battery. Use a good fuse or circuit breaker (preferred) in the front. Use the correct guage for your compressor(s). You can use either terminal on the solenoid. Then run a jumper to one of the smaller terminals.

On the left you will see the grounded in cab switch, thru the pressure switch, then to the other small terminal on the 'noid.

Pretty easy and sanitary to set-up. This way there is no need to run another power wire to the switch and down to solenoid....less chances of shorts too.

Also can run a small fuse to the small terminal as well.

Hope this helps


Hey...just noticed, your the guy from Lodi....I recall telling you our other wherehouse is off of Turner and 99.

[62scraper]

Thanks for the pic, that really helps. So I dont need 4 prong relays? I am just trying to get all the parts together so that when I am off in January I can wire everything. What kind of warehouse is it? Is it a fab shop?

[ChiefRocka]

Well you can run the relays instead of the solenoid. One relay per compressor, or a HD solenoid for both compressors.

Just make sure that 'noid does infact ground thru one of the terminals.

If you want to use relays...here is the schematic for that...using the ground interrupt....




You battery wire for two compressors should be at least 8 guage.

The jumper only needs to be 14-16 guage as it is only 'clicking' the relay...the same goes for the ground circuit leading from the cab to the air-system.