Ran into a strange one today, had a 3406E that the Jake was not working on, replaced the clutch switch which had a broken arm, now the jake works, but only if the brake pedal is depressed. And no the clutch switch is not near the brake pedal. Acts as though computer thinks it has an automatic and is looking for a brake signal.
Was it operating like that before the clutch switch broke? I have been told some trucks have a setting in the ECM that only allows the jake to operate with the service brakes actuated.
According to the operator it was working fine. There are 4 brake switches that I can see, 2 on the tredal valve, and 2 on the firewall, so thought wires may be crossing, however the wires to the clutch switch are on the other side of the firewall in a separate loom to the computer, and the throttle is drive by wire. Its in a westernstar so finding a wireing schematic may be problematic. It acts like the computer is looking for a brake signal, but don't understand why it would have changed.
That is normal operation if the cruise is on, is the cruise on-off switch shot also?
You are right cruise switch is on, driver figured it out on his own and didn't let me know it was ok. We are allowed to ask stupid questions on here as well as smart questions correct?
I don't know...I never tried asking a smart one.
No such thing as a stupid question IMHO.....
I know of a few guys around here that never could figure out why you had to press on the brake to make the Jake work and they had plenty of experience. One guys method was to pull the Johnson bar to make the brake lights come on so the Jake would work without hitting the brakes, (solo dumptruck).
After 25 years in this buisness I thought i knew some stuff, problem is you can't know everything. It is good to be humbled once in a while. I have fixed numerous electrical malfunctions for this outfit, and I got called in on this one after the owner and there maintenance mechanic had scratched their heads for a while. The upside is I hadn't taken the dash apart looking for the issue, after 10 minutes with a meter I thought something just doesnt feel right and stoped. Well my father allways said you can loose 10 atta boys with 1 what were you thinking!