Over drive fuse for Ally OD button??

[John Wood]

Is there a fuse (and where) for the overdrive function. Pushing the OD button doesn't seem to have any effect on my 2004.5 Duramax Allison tranny.
All best - Woody

[DmaxMaverick]

Welcome aboard!

The circuit is low voltage, and isn't independently fused. The switch is momentary, as in not a "toggle". Does T/H work? Or is it just the OD lockout function? There have been a few reported issues with the harness entering the column, when the wire breaks from repeated flexing. If it's ONLY the OD lockout that's a problem, I'd suspect a gremlin in the TCM (or other tranny or sensory errors), and not the switch.

[John Wood]

Thanks much - your diagnosis was spot on. We replaced the OD button harness and that fixed it - hooray!!

[DmaxMaverick]

Glad you got it fixed. Sometimes things are just that simple.