baldygit

Member

• Jul 24, 2019

• #1

Hi. I have a problem that the gauges show overheating and the fuel is high. So I changed the voltage regulator. Trouble is the new one blows the fuse on the wiper/indicators/guage circuit! So I tried another and the same. Any Ideas?

 

ExMil109

Active Member

• Jul 24, 2019

• #2

Sounds like a short to earth somewhere, maybe caused by pulling the dash out to change the stabiliser. Check the input wire to the stabiliser (green) and then try disconnecting the feed from the stabiliser to the gauges (light green wire). If the fuse still blows, it's likely the stabiliser itself is faulty. If not, check if the light green feed is shorting to earth somewhere. Good luck!

 

baldygit

Member

• Jul 25, 2019

• #3

Many thanks for that. I will give it a try. It's a bit of a nightmare behind the dash. Not a lot of room!

 

tottot

Well-Known Member

• Jul 25, 2019

• #4

I remove steering wheel when working on dash.

 

baldygit

Member

• Jul 26, 2019

• #5

That's a great idea! Will do that. certainly make access easier

 

Blackburn

Well-Known Member

• Jul 26, 2019

• #6

Take care when removing the steering wheel slacken the nut but leave it slack on end of shaft , then bash wheel up from below with your hands .
I forgot awhile ago and wheel was tight give it some welly and it hit me on the nose very painful.

 

baldygit

Member

• Jul 30, 2019

• #7

Thanks for that. I had a good look on Sunday. Had the dash out and cleaned up the fuse box etc. Nothing was obviously wrong. Couldn't see any dodgy wires or loose anything. When testing the new voltage regulator I discovered the casing is live when 12v is attached! Is that right? 'Cos surely when screwed back down properly to the back of the clocks it will short and blow the fuse? Thanks for any help.

 

ExMil109

Active Member

• Jul 30, 2019

• #8

The regulator case shouldn't be live - that will blow the fuse for sure. But be aware that the regulator has a coil inside between the output terminal and the case, so the casing may appear to be live when checked on the bench with a multimeter. You could check the resistance between the input terminal and the case - I don't have one handy to check, but I'd expect it to be around 100 Ohms - if it's way lower (or zero) then the regulator is likely faulty.

 

mystery

Well-Known Member

• Jul 31, 2019

• #9

have a look http://www.britishv8.org/Articles/MGB-Voltage-Stabilizer.htm

 

mystery

Well-Known Member

• Jul 31, 2019

• #10

and https://getrid.my/blog/2018/08/20/voltage-stabilizer-on-many-classic-cars/

 

baldygit

Member

• Jul 31, 2019

• #11

Well, I just checked and the casing is all definitely live when connected. Also the resistance on my multimeter (set at 20k) reads 0 between the input terminal and case. Then 4.70 between outlet terminal and case! The crazy thing is, the replacement that Paddocks sent is the same??

 

ExMil109

Active Member

• Aug 1, 2019

• #12

I think you've got a dud regulator (or two). I've heard similar complaints on the forum before, even with new replacement parts. You could try Dunsfold for a genuine one (likely to be expensive though) or you could open it up and see if the input terminal is touching the case somewhere - mystery's link has good info on how to dismantle it.
A lot of owners are going for replacement electronic regulators - not tried one myself, but might be an option, especially if you're handy with a soldering iron...