Mitch Haley wrote: > I believe Ford had a gauge option in the 7.3 PSD with four speed. Sort of an > on/off gauge like the engine temp of the same vintage. It had two readings, > "OK" and "please deposit $3,000". Supposedly the idiot lights with needles > result in fewer service calls than real gauges, some owners would bring their > truck in under warranty if a temp gauge started reading higher than when new, > so Ford designed a gauge that always read the same unless there was a real > failure.
Volvo 240 temperature gauges are the same way, from '86 on. They started adding a "temperature compensation board" that divides the temperature range into three categories -- cold, OK, and hot. The gauge reads in the center as long as the temperature is in the OK range, then is driven to the upper peg when it reaches hot. The motive was supposedly the same, to reduce warranty claims. The boards have a tendency to fail, and the basic gauge is still the same, so like a lot of people I removed mine and soldered a jumper in its place. I don't really appreciate that sort of chicanery.