Wonder if Warren ever found out what the issue was?

I agree john, most clark forklifts have an alarm sound if truck has been powered down or keyswitch turned off and parking brake has not been applied, I would definitly try that first.

I just had a revelation, I recall when I sold Clarks when you dismount the lift you better apply the parking parking 'cause if you didn't that horn will sound when you are about 10' away from the lift & scare the crap out of you. Clark does it this way because OSHA states that the parking brake "shall (must) be applied when the truck is dismounted and the operator is more than 25' feet away from the lift or out of the operator's sight. So this horn activation is tied into the operator presence switch in the bottom portion of the seat and the parking brake actuation mechanism and there must be some sort of switch, like a micro switch, acuated by the P/B foot lever. This assumes the ECG you have has an original OEM seat for electric lifts with a switch in the bottom cushion properly work & connected. Those seat are very expensive and someone may have installed an almost like an OEM seat on the cheap - just a SWAG.

I'd contact your local Clark dealer & give them the model & serial #'s & have them check what options your truck came with. The technical book you speak of- is at a service manual? If not, I's suggest ordering one before poking around the wiring- you could cause more harm than good by accident.

Well thats what I was thinking as well. However there is a seatbelt indicator on the instrument panel. And a bell sound that goes off. after digging into the lift more there is a solid state relay timer that is also wired into the horn thats supposed to sound when the directional switch has chaged fwd or rev. I'm thinking I may have an issue with that component. But I did try the seat belt was a no go but thanks for your time.

yes most trucks now come with an operator presence system that requires the operator to have all safety devices enguaged, ie: seatbelt , seatswitch etc locked in.

so as john put it, fasten the seatbelt and you find the horn will not sound. The parking brake may also be tied into this circuit so if it is not set when the operator gets off the lift it will sound off.

Try buckling up the seat belt with the operator in the seat then turn on the key switch and see how quiet things will be. Kinda, like that seat belt warning noise in you car that many with a death wish try to disable.