How to wire a relay? *HELP*

[Houston hb]

I needed to use a relay so i can get some extra power to a compressor in my trunk of my RL. The problem im have now is that the compressor is getting power from my tow hitch wiring and sometime its underpowerd. Its start out going strong and then it drop down to a slow hum. I remember my friends where telling me that using a relay can give a item extra boost of power.

The problem is that I dont remember how to wire it up and coming from the tow hitch harness its 2 wire only, 1 pos and 1 neg. Can a relay be ran from 2 wires to feed something else.

cliff notes
- Need to wire a relay w/ a inline fuse to give more power to a compressor.
- Using 1 pos wire and 1 neg wire , from tow hitch
- Relay has 87, 86, 87a, 85, 30 what goes where

Ps sorry about the fast writing trying to know this out asap

[KE5TCG]

Originally Posted by Houston hb

Its start out going strong and then it drop down to a slow hum.

That is not good. It is cause for concern. Sounds like you are overheating something...like maybe a wire not rated for that current. You may doing damage to the vehicle's electrical system.

A relay doesn't boost current on its own. It is just a switch to let another source of power through. Your friend's relay probably had another direct wire to the fuse panel or battery.

Not to be harsh, but from what you said it sounds like you're not familiar with electrical wiring requirements. Electricity is not a good arena for trial-and-error learning by experience. Just FYI.

So, please don't make our insurance rates go up by your having to file a claim after burning your truck down. Please?

[BruceRTL]

Originally Posted by KE5TCG

Not to be harsh, but from what you said it sounds like you're not familiar with electrical wiring requirements. Electricity is not a good arena for trial-and-error learning by experience. Just FYI.

I agree! Be very careful here...

It sounds like a capacitor is more in order for a quick boost of power. Now there's a toy that can curl your hair (if I had any). I think it's time for professional help sir. We don't want a "CARbecue".

[HH4]

Where are you getting the power from the hitch wiring? If you are using a lighting circuit from a 4 pin plug you will overload the circuit with a compressor. A relay will not help in this case unless you run a seperate circuit direct to the battery for the compressor. If you are using the charging circuit from a 7 pin setup , this should have more than enough capacity to power the compressor and a relay would not make it any better.

If the compressor will not run right on the power available from the charging wire at the hitch harness, there is almost certainly a problem with the compressor or the wiring to the hitch.

[shovelhd]

Is your tow hitch power using the Honda harness or a tap? I would never run an air horn compressor off of a tapped line. That's asking to burn out your compressor and/or set your truck on fire.

The best way to handle this is to run a completely separate circuit from the battery, fused within 18" of the battery. The chassis ground should be ok.

[Houston hb]

well im running the taps off the 7 pin, connector. I thought about soldiering the wiring down and then also I thought about maybe the wires to the compressor are alittle to long and I should shorten them a tad.

[Houston hb]

Originally Posted by shovelhd

Is your tow hitch power using the Honda harness or a tap? I would never run an air horn compressor off of a tapped line. That's asking to burn out your compressor and/or set your truck on fire.

The best way to handle this is to run a completely separate circuit from the battery, fused within 18" of the battery. The chassis ground should be ok.

Im using the honda trailer hitch and harness

[shovelhd]

What is the compressor circuit rating, according to the manufacturer?

[Houston hb]

Originally Posted by shovelhd

What is the compressor circuit rating, according to the manufacturer?

Viair 280 Air Compressor
Voltage: 12 Volts
Max Amperage: 16 amps
Maximum Duty Cycle: 30 % @ 100 PSI
Maximum Working Pressure: 150 PSI
Length: 8.0”
Width: 4.0”
Height: 7.05”
Weight: 6.95 lbs

[shovelhd]

The compressor draw is 16A, and the trailer circuit is 20A. If the compressor is running and you hit the brakes, you'll blow a fuse. Not good. Run a dedicated circuit.