Low air/emergency lights

[profo]

Lately my low air pressure and emergency brake lights have not been coming on when I first start truck the warning buzzer works fine and shuts off at about 60 psi and buzzer comes on when emergency brake is lifted/pulled on, looked in TM's and replaced the two low air pressure switches on air tanks but pretty sure this only works the buzzer fail safe box, is there another pressure switch for these two lights and if so where is it located, I also found pressure switch on brake bypass switch on dash , I shorted wires together and also active this button and it works the brake bypass light ok! Any ideas?

thanks marty

 

[goldneagle]

I hate to ask, but could it be burnt light bulbs? Loose grounds?

 

[MtnSnow]

If the fail safe is working then usually its bad bulbs or bad grounds for the dash lights to not work or work intermittently

 

[profo]

Bulbs good, ground good I removed the wire going to each bulb and hooked to 24 v and they both light up does the fail safe unit drive the bulbs because I am not getting any voltage to the wires coming in, trying to figure where the voltage comes from for these two bulbs I dont know if it is from two air pressure switches or the fail safe unit, didnt find anything in the TM's yet I am thinking the fail safe unit drives these bulbs cause I kinda remember them blinking and a switch cant do that.

Thanks Marty

 

[simp5782]

580 comes out of the Failsafe module to the Low air light and 583 is to the parking brake light. 584 is from the Parking brake switch into the failsafe unit. 578 is from the air switch to the box. 57 is the box ground.

 

[74M35A2]

Which wire goes to the sprinkler valves?

 

[simp5782]

The one that was spraying water on your tailgate cause you wouldn't get that slow thing out of the way. In all honesty I thought I was following a M928A1 there for a second. Zero to 4th gear in 2 minutes.

 

[profo]

580 comes out of the Failsafe module to the Low air light and 583 is to the parking brake light. 584 is from the Parking brake switch into the failsafe unit. 578 is from the air switch to the box. 57 is the box ground.

Thanks finally found the drawing in the tm also it must be my fail safe not out puting or there seems to be if I am reading the diagram correct that one wire from fail safe go to light switch maybe there's a bad connection there do you know if you have the light switch to all off including tail lights if they disable those lights also I leave mine in the tailights on position all the time so the low pressure lights should still work cause they sometimes work, anyway I'll get a fail safe at rally if anybody has one the buzzer still works and I watch my gauges very closely when driving!

 

[simp5782]

No. They gather there power from the failsafe box thru the main battery switch

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[TCD]

Hi Profo,

Please list the TM #.

Thanks!
Tom

 

[therooster2001]

If it turns out to be the fail safe , I've got a couple of take offs in the classifieds. Borrow someone's to be sure.