MGB & GT Forum


Moss Motors
AutoShrine Sponsor
AutoShrine Sponsor
AutoShrine Sponsor
AutoShrine Sponsor

jjh1118 Avatar
jjh1118 Jim Hargrave
Bogota, NJ, USA   USA
1975 MG MGB "The Little Car"
So, I'm leaving a local car show Friday night in my 75 B. I press the headlight switch and it self destructs. A very scary ride home in the dark! I know,I know, I know,not smart . SWMBO already clued me into that. Once safely home I ordered the headlight switch and a new Hazard switch ( still working but the top was broken ). Installed both today and I have headlights. Dashboard lighting is good , Tail lights and parking lights operational too, front side markers are a go! Here is the issue: rear side markers no, turn signal indicators on the dash - right side good , left side - on steady - no blinkie . Are these something with the installation of one or both of the switches or a coincidental, problem? Also in my attempts to get the broken switch to work enough to give me lights for the ride home I dislodged a wire bracket from Behind the dash. I see it listed in Moss catalogue but I have no idea where it goes or what it's purpose is. I hope this gives you guys a couple of chuckles and something to get the gray matter stirred up.
Any insight provided is greatly appreciated.

. Hide banner ads & support this website by becoming a > Gold Supporting Member <
gofastandfalldown Avatar
gofastandfalldown Glen Horne
Edmonton, AB, Canada   CAN
1970 MG MGB MkII "Miss Pandora Moneypit"
I don't know the answer to your problem but if it ever happens again, hold the flash-to-pass stalk toward you. This will force the high beams on, as that circuit doesn't go through the headlite switch. No tail lights, but at least you would be able to see.

Gokart Avatar
Gokart Silver Member Rob Illingworth
Palmerston North, Manawatu, New Zealand   NZL
As the rear side markers are on a different circuit to the indicators and the right indicators work but the left don't blink, I would hazard a guess (pun intended ha ha) that your grounds need checking and cleaning.

The indicators get their power from the same source, the flasher. As you have one side working and the other not so much, I would bet on the grounds (check other connections as well for corrosion).

The front marker lights get their power from the top fuse and the rear marker lights get their power from the second fuse down and both those fuses are supplied from the same red/brown wire from the dash light switch. As it is only the rear side markers not working it is most likely the ground not connecting properly.

The ground is attained through the light fixture bolts through the body with the nuts being the best contact area for the ground to go through. The nuts are usually pressed sheet steel items with a flange area going out from the bottom of the nut. This flange area usually has a couple of hooks on the outer edge to bite in to the contact area presumably. Clean out these contact areas and I would be hoping for a much better result.

Download MGB wiring diagram from here,

Cheers Rob

Edited 1 time(s). Last edit at 2017-09-14 04:37 AM by Gokart.

. Hide banner ads & support this website by becoming a > Gold Supporting Member <
jjh1118 Avatar
jjh1118 Jim Hargrave
Bogota, NJ, USA   USA
1975 MG MGB "The Little Car"
Great info ! Thanks to all.

Jeff in Iowa Avatar
Jeff in Iowa Jeffrey J
Iowa City, IA, USA   USA
1970 MG MGB
Originally a lot of power went through the headlight switch leading to failure. I upgraded to halogen lamps and installed relays to power them.

. Hide banner ads & support this website by becoming a > Gold Supporting Member <

To add your reply, or post your own questions

Registration is FREE and takes less than a minute!

Having trouble posting or changing forum settings?
Read the Forum Help (FAQ) or contact the webmaster

Join The Club

Sign in to ask questions, share photos, and access all website features

Your Cars

1980 MG MGB Limited Edition LE

Text Size

Larger Smaller
Reset Save

Sponsor Links