[Mgs] B/GT electrical problems

[Robert's New iPad]

  The line voltage stabiliser is common to both Tach and Fuel gauge, and is always suspect. They do, however, tend to last many years (unless they don’t).  
   What I would do first is to ensure that both wires on the coil are secure. One excites the tach, and if the connection is dodgy the tach can be erratic.  Also check the fuses, as they are frequent suspects too, though unlikely in this case.  Loosen, then tighten, the screw securing the stabiliser to the bulkhead. Good connection for earthing is important.  
   WIth an old-style, needle-type analogue voltmeter, check the output voltage of the stabiliser. Awkward to get at, but it must be tested in the car. Voltage will vary, if it is the original points-type stabiliser, swinging the needle up and down the scale, but you are looking for a mid-point average of 10V.  If yours is the newer type, electronic, it should be steady at 10V.  
   Because the temp jumped as it did, I would recommend that you also use an infrared thermometer to check actual temp at the thermostat.  They can fail unpredictably.
Bob


> On Apr 9, 2021, at 11:29 AM, S.Carr <britfan1 at epix.net> wrote:
> 
> #1 – tachometer – after working sporadically, the tach in my ’71 B/GT has finally quit completely.
> #2 – temperature gauge – until we started it up this spring, the gauge has never been above “N” (except for one long uphill crawl with a loose fan belt).  Now, after only a few minutes at idle, it went rapidly to “H”.
>  
> Would either of these problems be due to a problem with the gauge voltage stabilizer?  The wiring diagram shows wires going from both of these gauges to the stabilizer.  I have a vague memory of having a stabilizer fail years ago, and some of the gauges not working thereafter, but I don’t remember which ones it was.  Wisdom of the List?
>  
> Thanks in advance,
> Sarah Carr
> ’71 B/GT in PA
>  
> Sent from Mail for Windows 10
>  
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