pressure switch being grounded question

Edited: 6/5/2006 4:28:35 PM by madmax95

Edited: 6/5/2006 4:24:17 PM by madmax95

Edited: 6/5/2006 3:19:14 PM by madmax95

Edited: 6/5/2006 2:48:35 PM by madmax95

Edited: 6/5/2006 2:46:56 PM by madmax95

Edited: 6/5/2006 2:45:45 PM by madmax95

ok, i see this diagram and it shows the pressure swtich going into the relay and then the other wire going to a 12 volt source and the relay being grounded grounds the pressure switch?
http://www.suicidedoors.com/how_to/wire-diagrams/compressor.gif
my q is right now i have the pressure switch grounded to my tank( and it has two wires, one blue-for realy and black, the black is suppose to go to a 12v source?or ground?))
should the relay it self be grounded?

any help would be great. thanks alot
********please also read post 3. thanks
and my last post oo if you can. thanks

Edited: 6/5/2006 3:22:49 PM by madmax95

Edited: 6/5/2006 3:20:41 PM by madmax95

ok, thanks alot. my relay isnt really grounded, it has my compressor going to it,( grounded) my 12v source ( amp-grounded)) my pressure switch( grounded to my tank) and my ignition going to it, dose that seem right? ive been haveing problems, my ignition was working to were id start the car and the compressor would work, now it doesnt work when i turn the car on and its not the relay,( i tried two) does anyone know what my problem is? i just want to ride. thankswhat can i look into for? any info will help alot

Originally posted by minimazda5



you should make the p-switch ground your system, run your ground off your relay to the p-switch then from the p-switch to a ground, that way there is NEVER any + going through it and you should never have to replace the pressure switch.

Running it the other way (12v+ thru p-switch) its quite possible to burn up a p-switch, ive done it before, switched to the grounding method and havent had a problem since....

nope nope nope.

There may be +12v going through the pressure switch, but the current needed to trip a relay is ~300ma. Thats less than a dome light. This will blow your mind, wiring it as grounded does not change (not even a little bit) how much current goes through the switch. Its just 300ma of -12v.

Now, if you took the relay OUT and used the press switch as the sole link for current to the compressor, THEN you might burn one up. But to just trigger a relay, thats the low current side of the relay, no danger, 85 gets either 12 +/- and 86 gets the opposite of whats on 85, doesnt matter how you apply it. Thats the definition of relay, the low current "switch" in 85/86 hands off the high current responsibilities to the high current contacts in 87/30.

Nothing needs to "ground" the pressure switch, it is a mechanical switch where high pressure pops the contacts open and low pressure allows them to touch again. If it were an elctronic device, it would have another wire.

oh and its a adjustable pressure switch too if that means anything,( two wires on it, blue and black) an e.a.i. one.

it sucks, i paid good $$ to have it hooked up and now im haveing problems. it was working, but like i said, when you start the car, the compressor should kick on, it was, but not now. does anyone have an idea why if its not the relay? im also worried its hooked up wrong somehow. i have to touch the amp wire ( my 12v source) to my compressor to get it to run and i dont think thats safe, right? and now with all my problems, next time i do something like this, im going for it myself.

Originally posted by madmax95



it sucks, i paid good $$ to have it hooked up and now im haveing problems. it was working, but like i said, when you start the car, the compressor should kick on, it was, but not now. does anyone have an idea why if its not the relay? im also worried its hooked up wrong somehow. i have to touch the amp wire ( my 12v source) to my compressor to get it to run and i dont think thats safe, right? and now with all my problems, next time i do something like this, im going for it myself.

could be a loose connection, or bad pressure switch. take a volt meter and see if your pressure switch is working, then check your relay out too

Edited: 6/5/2006 4:00:35 PM by madmax95

yea, i got a volt meter from work today. when i check it, the car should be on? just touch the adjustable pressure switch blue wire?9 it has a blue and black wire) when its hooked up too the relay? this is a first for me guys. and if i do get voltage, its probably something to do with the ignition switch? but it was working, so what would make it go out if its a ignition problem?

I agree with Russ-D

Edited: 6/5/2006 4:06:30 PM by LKrayzie

when you test it you want everything to be on, start inside your truck, make sure the wire that goes from your fuse box to your pressure switch has power. then check your other side of the switch to your relay prong 86. check your relay ground 85. and last you want to check the prong goin from your relay to your compressor, 87. you said you have power comming from your battery. take it one step a time

Edited: 6/5/2006 4:22:56 PM by madmax95

Edited: 6/5/2006 4:21:50 PM by madmax95

Edited: 6/5/2006 4:21:03 PM by madmax95

^^thanks man. its a 95 maxima i got. it just sucks cause i just got the air hooked up and now problems. ( which is ok, but when dude says "its all gravy" and shit, it pisses me off. it was working. so, i have the 12v power (amp), compressor, pressure switch, and a blue ignition wire that goes from under my dash to the relay hooked up in my trunk). all of those go to the relay in my trunk) does that sound right?