sleepwheel,
what edwardt says is the way things could play out if you do not get a handle on the situation at this customer and make them understand the implications behind bypassing systems on these trucks. Also the lack of maintenance is the sole contributer in the shape these trucks have gotten in.

I surely hope you have documented all cases where he has refused required maintenance and had you bypass circuits.

The company i work for issues thier techs some stamps that we are required to use when we come across situations such as this, these stamps we use are "safety alert" and "abuse" stamps. When we come across such a situation we have to write up in detail what we find and stamp the workorder before we get it signed. THEN at the point of the customer signing we are required to explain to the customer why this is on the paperwork and give him the option to correct the discrepancy or not. IF it is a safety violation i strongly urge the customer to make the repair for obvious reasons, most of the time they make the repair due to the nature of the situation. Of course the "abuse" stamp is self explanatory and just lets the supervisor know he has a careless operator that is tearing up the truck from careless driving.

Now in the case of the BDI bypass, this is not necessairily a safety device but it is designed to keep from damaging the battery and/or the systems on the truck. By bypassing it your creating a situation that will probably in the short term cause a myriad of other issues that will crop up from low voltage/high amperage and wind up costing the customer alot more money because of it. I usually do a pricing comparison for the customer to show him the current cost v/s the predicted cost if he refuses the repair at that time. I know there is no way to predict a future breakdown but if you are articulate enough you will be able to give him a general idea, if he is as money concious as he seems to be i'm sure he will do the right thing. This is the point you have to make him understand, he may bawk at it and in the end even still refuse the repair but like edwardt says, CYA (cover your azz) and actually your covering his too by explaining this to him, it also puts the ball in his lap :o)

If you do it right, he will probably understand and be more reptive about it. But then again he may just be the type of customer that wont and your wasting your time. The main point is to make sure he knows whats going on and make sure your covering yourself and your company too (if you work for one) If your independent then it would be imperative to do so for your own survival. A lawsuit could break you and ruin your reputation.