I'm working on a 97 GMC Savana - Braun Bus coversion. Equiped with a Penn-Tex High Idle controller. It sets high idle during a low voltage event, (with A/C & wheelchair lift) Controller lights the LED to say it's calling for high idle - but doesn't idle up. Traced out the line to the ECM, and grounded directly - no idle up. Checked and had system voltage (14v) to ground, so connection is there.

Thoughts?