Firestone 9039 Replacement Pressure Switch

Bought this switch as a direct fit replacement for the one I had that burned up and it works great and fit great but after inflating my air bags the switch will not deflate them. This is a little annoying as I don't like to keep the same in them when I'm just driving my truck as I do when Im towing the fifth wheel. Don't know if this is a faulty switch or if this is the way they are but the reviews did not reflect this problem. If its faulty it would be nice to get another.

Bought this to replace the original that some hack installed to power the compressor sans-relay. The original switch had of-course died a horrible electrical death that follows the terrible misapplication of electrons. Its successor (this one) does what it should, triggers the compressor while opening the air-flow path, so it gets 5 stars. No leaks, air bags are happy again. I did not use the included wires as I'd already rewired the old switch properly. Plug and play. The wires were VERY tight and hard to remove but I'm ok with that. Makes them not likely to rattle off when installed. Air connections are barb fittings which was like what it was replacing for me but something to be aware of. I carefully heated the old ones with a heat gun to soften them up for removal/reinstall.

The previous owner decided to bypass installing the relay and running the pump off the switch. Lesson in electronics: ELI the ICE man...Voltage leads Current in and inductive circuit...So every time you open the switch the voltage rises to technically infinite. This is why you get a big spark on a vacuum cleaner when you pull the cord while running. The high voltage will and did ruin the switch. Amazon to the rescue!

Used switch on a 2008 Kenworth T170 dump truck driver seat. OEM switch has 90 degree brass air fittings on back of switch. This switch has them coming straight out. Really need 90 deg. fittings on them for clearance. No big deal, but this switch is gray on the front and factory switch is gray also.

a1

Exact fit fast shipping a little pricey

As described

Opened package today, found product to have been melted before being returned to amazon as well as being the wrong part. It is just an air valve, not a switch.

Was an exact replacement and is working perfectly.

Part arrived in a timely manner & saved quite a few dollars by being able to order switch on it's own, without gauge a mounting bracket.

Part didn’t work correctly

Good