interesting CTIS issue

[ZiggyO]

Hello all,

Working on a buddy's lmtv, I came across something I haven't seen before. I have no lights on the ctis controller at all, but it is working perfectly-- it comes online as it should when air pressure builds, and goes through the pressure checks, and will inflate/deflate when various modes are selected, but there are no lights indicating which mode it is in. Has anyone ever seen that condition before?

Z

 

[Andyrv6av8r]

Some trucks have to have the headlights on to power the lights on the controller

 

[spankybear]

Pin "S" should be the block out input.

 

[ZiggyO]

Just an update: checked incoming power, and swapped out another controller-- the second controller lights up and functions properly, but the first still does not light up but also functions properly-- still a bit stumped but it is definitely in the controller itself. I just don't know if I want to dig into it further seeing how it functions properly, but has no red lights..........

Z

 

[Ronmar]

Like Spankybear said, pin S on the controller cannon plug provides power for the Controller lights and for the controller to switch the ctis overspeed light on and off in the dash. That power(from the CTIS CB-40) arrives via the de-energized contacts of K-52. When you turn on the blackout lights it energizes K52 and removes that power from pin S and blacks out the controller and overspeed light...

Nothing to work on in the controller, it is brutally potted inside of it’s case...

 

[spankybear]

Do you still have this unit? what color is it and can you take a picture of the part number tag on the bottom?

 

[spankybear]

Replace K52 relay. It is a 5 pin 12 volt coil relay. Also check CB40. This is a 24 volt supply. One of these could be your issue.