Engine brake not working correctly

[ed563]

07 IH 9900i
500 ISX

3rd position on the engine brake switch doesnt work.
1st and 2nd positions work, but when i flip it to 3rd i cannot notice any difference from 2nd to 3rd.

What would cause this? Should i Swap out the switch? Or is there an electrical wire harness or something that could have came apart?

Anybody got any info on this topic?

[ralph]

You can check the switch with a test light to see if there is power going through the switch on the 3rd position.

[Maxx]

If its not the switch, check for a broken wire between the switch and the brake controller. Some of these harness are impossible to figure out. Good luck with it.

[ed563]

thnx fellas

[hevhauler]

If u have a boost gauge watch it when u switch from 2nd to 3nd stage u should see a increase in boost.

[ed563]

i did not kno that. thnx for the info hev