Re: Re : oil temp gauge accuracy

[steveb@falcon.kla.com (Steven Buchholz)]

> Help
> I own 87 4q w/115k
> Problem is this, the volt/oiltemp bar lights by the diff selector
> switch work fine when there are no lights on. As soon as I turn
> on the head light switch either to the first or second position,
> the oil temp light goes balastic..Sometimes even reading off the
> scale...Anybody got a clue before I start replacing or forgetting about
> it?
> >
> Some of these panels are sensitive to input voltage. I have a few of 
> these diff lock panels and on one there is a noticable jump in
> oil temp when the lights are turned on. I have replaced it with 
> another panel and this one doesn't have the problem. One time
> with a conversation with Ned Ritchey, he said that the oil temp
> display likes an input voltage of 10.5 volts. But you need to make
> sure that you only regulate the voltage to the oil temp LED and 
> not the voltage LED.
> -
... this same effect can occur with the analog gauges.  I know that on 
my '78 Fox (and other cars) that the power supply came from a switched 
circuit that also supplied the blower fan for the passenger compartment.  
I seem to recall that there were some changes in the way the grounds 
were connected as well.  You can probably help your case by providing 
an independent power and ground for the gauge panel ... don't forget 
to find a power source that is switched!  (yes, I did end up with a 
constant voltage reading with Rev A ... :)

HTH!
Steve Buchholz
s_buchho@kla.com
San Jose, CA (USA)