low pressure air alarm not working properly, ADVICE APPRECIATED

NOW THATS WHAT IM TALKING ABOUT! I just got up and going to brew some coffee, id like to finish this problem off pnce and for all today...i am stubborn, driven (and NOT mechanically gifted)....but usually get whatever mess fixed in the end

 

First, make sure this is the dash cluster you have or at least that the connectors on the back look the same.



This is the cluster tilted back out of the dash. I've removed the blue wire retainer just for clarity.



This is where the wire on circuit 18 connects to the ICU



And closer up...



If this wire is disconnected from the cluster, the low air warning light and chime should come on and stay on. If you ground this wire, the light and chime should go off completely.

If it does not work like this, then there is likely a problem with the cluster itself.

This is how to wire it so it works like it should...

 

BRILLIANT! my cluster is indentical. I am varnishing wood in sleeper atm will attack this problem with your suggested diagnosis in anhour or two and report back. Again wow, THANKS.... if i ever get this beast rolling ill buy you steak dinner

 

This is what the low air chime should sound like during a self test. If it doesn't sound like that, possibly the chime in the ICU is bad.

 

Dash looks identical but wiring on backnside is different. All yellow wires, two bundled sets. I cannot identify tge wire you are indicating.

 

Yes icu chime correct. Waaaaay too quiet when truck running.

 

Hooking it up to the eternal buzzer with air switches primary and secondary running parallel i now get 6.8volts to buzzer....much worse than the 10.5 i was getting befor (which was too weak to power buzzer or light)

 

CORRECTION, hooked up to external buzzer it is at 6.9volts unhooked 10.6v. Parellel schemtic is correct but voltage still too weak

 

Ihave to literally flick buzzer to turn it on