Air compressor installation

Submitted: Monday, Jun 11, 2007 at 09:59
ThreadID: 46515 Views:1927 Replies:3 FollowUps:2
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I am trying to install a Bluetongue air compressor in my vehicle, but when you are 12 volt challenged like I am, the simplest things can prove to be mountains.

I have installed the pump in the engine bay, and have installed a relay on the firewall and have earthed the pump using the firewall as well.

I have connected power from the battery to terminal 30 on the relay (including a fuse), connected the pump to terminal 87 and earthed the relay using terminal 85.

I have installed a Carling switch (with light) on the centre consul, and this is where I am having trouble. How do I run the cables from the relay (terminal 86) to the Carling switch to make it all work and power the light?

The Carling switch is a simple on/off switch with 4 terminals on the rear.

Please be kind and keep it simple
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Reply By: donk - Monday, Jun 11, 2007 at 10:20

Monday, Jun 11, 2007 at 10:20
If you look at this wiring diagram for driving lights & substitute your compressor for the lights & the power wire to your switch with the power wire to the high beam (that energises the relay) it should be strait forward

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Regards Don
AnswerID: 246028

Follow Up By: donk - Monday, Jun 11, 2007 at 10:25

Monday, Jun 11, 2007 at 10:25
You need to have 2 power feeds to your relay

Regards Don
FollowupID: 506967

Reply By: _gmd_pps - Monday, Jun 11, 2007 at 10:53

Monday, Jun 11, 2007 at 10:53
2 pins on your switch are for the light and two are the switch
the light needs to be grounded on one side.
Take a positive from inside the cab (I have installed a separate little fuse box)
run it to the switch on one side .. run the other side of the switch to your relay and also connect the other side of the lamp to the switched wire.. the lamp will light up when you switch on .. if the light is a LED you have top check polarity (which side is + ) ... If you have trouble and are in Perth .. am happy to help ..
AnswerID: 246033

Reply By: Bonz (Vic) - Monday, Jun 11, 2007 at 15:11

Monday, Jun 11, 2007 at 15:11
Almost right it goes like this, 30 to battery, 87 to load (Pump)

85 ok to be earth, 86 goes to your switch and the other side of your switch goes to a 12v positive (power) pickup somewhere in the cabin.

The carling switch will have 3 connections, power in, power out and earth, the earth is for the light, and is usually the middle one, if you cock up the other two the light will stay on so just change them over.

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AnswerID: 246083

Follow Up By: Tim HJ61 (WA) - Tuesday, Jun 12, 2007 at 00:14

Tuesday, Jun 12, 2007 at 00:14
Like Bonz says.
Thick wire carrying the load current from the battery, fuse relay and pin 30.
Thick wire carrying the load from pin 87 to the load - pump.

Thin wire is used only to switch/energise the relay on the other connectors, low current needs.

Relays enable you to have light wiring running back to your dash for switching on and off, and shorter heavier wires carrying the current close to the power source and the load. You don't have to use relays and could run heavy cable from the power source, to the switch, to the load. But they make life a lot easier, safer and electrically efficient.

FollowupID: 507133

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