Viair relay troubleshoot

do you have a pressure switch?

yes

Ok, from the pics that you have posted do the two red 8 GA wires that are taped together go to the Battery or the Compressors? I notice that you have small GA black wires on both side posts? It looks like you have the negative pressure switch wire running to the wrong post (looks like it goes to the right post and not the left). That might be your problem.

Put the relay on a table with the mounting side down.

1. The post at the top of the relay goes to the power or positive side of the compressor

2. The post at the bottom of the relay goes to the power or positive side of the battery

3. The post on the left goes to the negative side of your pressure switch.

The two 8g in the back come from a fuse then to 2g to the battery. The two 8g in the front go to the compressors. Black wire on the left ground. Black wire on the right pressure switch. The ground and pressure switch look wrong from the instruction pics but they are placed correctly as of the labbeling on the relays.

Try just grounding the wire that goes to the pressure switch. The pressure switch may be bad and is really not that uncommon to happen.

Do you have a meter? What is it showing at the relay? If you don't have a meter go and buy one for $10. It will save you a ton in headaches. It may be as simple as a bad ground, but from what you are saying it is wired correctly.

Also test the compressors and the grounds for the compressors.

Figured it out! The ground for the bed to the frame was broken and i had grounded the compressors to the bed. I feel like i need to wear a helmet sometimes!lol Thanks for the advice on where to start looking guys