imcengineer
New member
- 1
- 2
- 3
- Location
- Pittsburgh PA
I recently had a fail safe module go bad. I quickly realized it was an aftermarket version anyway so I figured I'd just make my own rather than try to dish out a couple hundred for a replacement. Everything was pretty easy to find with the help of the P2P program that shows the black box for schematics.
You will need:
1 x housing (I used 6"x4"x3", can be smaller with a cleaner install)
1 x Amphenol connector MS3102A18-1P
2 x inline MINI fuse blocks (not necessary, just skip from the wiring if you don't use)
4 x SPDT 24 volt coil relays with housings and pigtail wiring
1 x piezo 24 vdc buzzer at 85 dB
1 x 200 ohm 5 watt resistor (this was the hardest part to figure out as it was partially a guess and check method) Note, if you change out your low air pressure and parking brake bulbs to different wattage then you will have to adjust this resistor sizing appropriately.
1 x silicone for ensuring watertightness all around the housing
2 x aluminum or steel brackets to connect the housing to the mounting holes in the cab.
The buzzer isn't shown in the P2P program schematics. It's for low air pressure warning. I didn't want the buzzer to come on in BO mode for obvious reasons.
Once installed it works like a charm. In BO mode the parking brake and low air light barely glow. See attached wiring schematics and pictures of old vs new. If I had more time I could have scaled down the size of the new box. However it still works great.
Any questions please ask.
You will need:
1 x housing (I used 6"x4"x3", can be smaller with a cleaner install)
1 x Amphenol connector MS3102A18-1P
2 x inline MINI fuse blocks (not necessary, just skip from the wiring if you don't use)
4 x SPDT 24 volt coil relays with housings and pigtail wiring
1 x piezo 24 vdc buzzer at 85 dB
1 x 200 ohm 5 watt resistor (this was the hardest part to figure out as it was partially a guess and check method) Note, if you change out your low air pressure and parking brake bulbs to different wattage then you will have to adjust this resistor sizing appropriately.
1 x silicone for ensuring watertightness all around the housing
2 x aluminum or steel brackets to connect the housing to the mounting holes in the cab.
The buzzer isn't shown in the P2P program schematics. It's for low air pressure warning. I didn't want the buzzer to come on in BO mode for obvious reasons.
Once installed it works like a charm. In BO mode the parking brake and low air light barely glow. See attached wiring schematics and pictures of old vs new. If I had more time I could have scaled down the size of the new box. However it still works great.
Any questions please ask.
