Voltage stabilizer
 

A number of gauges on my 1973 1800ES are not reading correctly. Following advice elsewhere I have bought a new voltage stabilizer before embarking on wholesale replacement of the gauges.


But (somewhat embarassingly) I cannot find the old one. I assumed it would be up behind the dash somewhere, possibly attached to the back of one of the gauges. But I can't spot it! Of course I don't really know what I am looking for, as it may not look like the replacement one.


Can anybody point me in the right direction?

This may help.

http://sw-em.com/voltage_stabilizer.htm

I wish I could incorporate a stabilizer on my 6volt PV fuel gauge! The needle bounces all over the gauge when driving.

That's probably down to a bad rheostat on the tank sender.

Fairly new but I guess that doesn't mean for anything! When I get my finances sorted out I will probably try fitting a new one.

Thanks c1800, and top work (as always) from Ron.

It is the fuel gauge, oil temp and water temp gauges which are misreading, so it seems I may be on the right track.

"The stabilizer is mounted on the reverse side of the combined instrument" - whatever that is. I'll have to look more carefully. The Brickboard link says the stabilizer is mounted on the back of the oil temp gauge, so that's where I'll start!

put a 6v zenner diode in between the o/p sender and the gauge

http://www.reuk.co.uk/wordpress/elec...age-regulator/

https://uk.rs-online.com/web/p/zener-diodes/0463795/

Graham;

Your symptoms are consistent with a Voltage Stabilizer fault...to locate VStab, have a look at back of Tach or Speedo with a good light...sorry, they hid it pretty well, so some contortions are required...factory typically fastened them as a secondary use for the instrument securing hardware (giving continuous conductive path down to Dashboard metal)...but there might have been variations from the factory or mechanics which came along later...so remember: The Wiring Diagram Color Code is your friend...use wiring colors to verify you have indeed located the VS!...[White-GreeN looks to be input and BLue output for ES]
Be also aware, the Mount (M) hardware also acted as a chassis connection (important to the correct elec function of the VS!) so first thing when you locate it is to loosen, then resnug the securing nut to assure a good chassis connection (poor connection at VS mounting tab and any associated mechanical/electrical conductive path to Dashboard metal will cause malfunction including intermittency, although the "Chassis Tab" (C) of the VS itself simply wraps around the board edge and is held in-place by crimped over VS housing (see VS construction details below):
https://www.sw-em.com/voltage_stabilizer_study.JPG
Source: https://www.sw-em.com/voltage_stabilizer.htm
...this connection itself is susceptible after such a long time, to corrosion...)...to check function of VS, locate and connect a temporary test wire to the output of VS (best place is at one of the other instruments), and monitor voltage...VS output should be consistent with that shown in link (thanks also for reference, C1800!).

Let us know what you find!

Good Hunting!

Arcturus; Fuel Gauge with apparent Parkinsons (beyond that of simply following the bouncing float) on a model without a VS is another subject and you should probably open a separate thread. See also: https://www.sw-em.com/Fuel%20Gauge%20Notes.htm

Well, I found it. Up on the back of the oil temp gauge. right behind that support bracket which comes down from the dash top to the steering column. Definitely afterthought engineering. Probably seemed like a good idea when the dash was out on a bench.

I removed the steering wheel so that I had better access to the footwell. I probably should have removed the driver's seat too, but instead decided to break my back over the hand break lever and footplate. It was one of those jobs where (at my age) you pull every muscle in your body and get cramp in your fingers. Lots of little knurled screws at the limit of reachability. And wires that come off terminals before you have a chance to see what goes where. The wiring diagram colour code may be my friend but I didn't see a reference to DDG (dirty dusty grey).

Anyway my top tip is to access that top central gauge by removing one of the others first. I went for the water temp gauge which is the small one below it, but I should have bitten the big bullet and removed the rev counter.

In fact I ended up removing all of the gauges as the job developed (as they always do) into something else, and I decided to take the opportunity to refurb the bezels and clean up the dials.

Its all back together now, looking much nicer, and with everything working well (so far as I can tell - steering wheel is still off and I haven't run it long enough for the oil temp gauge to lift off its stop, but the life in the water temp and fuel tank dials leave me optimistic!).

Thanks guys!

Graham;

So what was the repair?...replacement of VStab or simply reestablishing its chassis connection?

...I see in first post you had a new one, so I presume you went ahead and installed it...probably a good move (you don't want to have to revisit that job again if you can avoid it...)...can I have the old one for a post-mortem analysis?

Cheers