I have a 85 GT and i am having a problem with the factory gauges fuel oil and temp gauges all read very low i was wondering if anyone else has run into this problem? every once and a while all of them will move up to where they are suppose to for a little bit would this maybe be a ground problem or something? Thanks mike 85 gt t-tops
I have the same problem with my 90 GT and those gauges. I'll be changing mine completely out using real gauges and dash insert from
Michael and JeanMarie McFarland opined in news:2rmNa.38345$fG.21782@sccrnsc01:
It's possibly a ground problem, but most likely the instrument voltage regulator. A little can on the back of the cluster with all the printed wiring. If I remember correctly it uses the same type connections as 9v battery.
Morning!
I have had this problem with my '85 GT (original owner) for many years now. I have changed the voltage regulator on the back of the cluster (9V battery kind of connection) and cleaned what grounds I can.
Till this day still does it! I too would be interested to hear if someone has the definitive fix!
Joe
This is my post from a year ago. It's now 3 years since I converted to
an electronic voltage regulator and still working perfectly. The only difference you'll notice is the needle movement is slower than the stock setup on engine startup but once they normalized the needles are rock solid, no more back and forth quivering. In retrospect, I think the root cause of my gauge problems may have been caused by high ambient temperatures in area of gauge cluster. (This fix is only applicable to '86 models & earlier because Ford changed to magnetic gauges beginning in '87.) Anyway, this what I posted last year:
++++++++++++++++++++++++++++++++++++++++++++++++++++ I had the same problem 2 years ago on my '86GT and it drove me nuts. Replacing the voltage regulator, checking all the chassis grounds and even connected a ground wire directly to the regulator failed to corrected the problem for me.What I did was convert the stock voltage regulator to an electronic version for less than $5 in parts. All I used was:
7805 fixed voltage regulator 47uF electrolytic capacitor 10uF electrolytic capacitor 6" of wire (about 24ga)I pried open the stock regulator, cut-off the contact springs. Use the remaining spring stubs to solder the input & output circuits to. I used a pop rivet to mount the regulator to the bottom of the metal case. Use electrical tape line the internal sides of the case prevent inadvertent grounding of the bare component leads. Although it was a little tight, I was able to fit all the components inside the case with a little planning. In retrospect, I may have substituted the capacitors with tantiliums for space considerations only because these are more costly. After that, just re-assembly everything back together.
You'll probably read elsewhere about the need to mount a 7805 regulator on a heat sink and also question the ability of it to drive
3 gauges (oil, temp, fuel) simultaneously. All I can say is that I've had absolutely no gauge function issues since the conversion and I'd recommend it to anyone.With the instrument cluster already out of the car, I'd suggest you that you check the "High' and "Low" calibration points with 10 ohm &
73 ohm resistors. If the needle is out of calibration, there 2 small serrated adjustment wheels on the back of each gauge. I'd recommend this procedure only for the oil & temp gauges. I didn't have much success with the fuel gauge calibration and I had to 'tweak' the "high" calibration a couple of times after the fact because with a full tank of fuel, it registered only 7/8 full.Enough of my ramblings.
Good luck.
C.J.
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