Checking the Starting Circuit

Simple troubleshooting steps for MGB no-start problems.

Written by Gil Dupre – 2007-02-10
How-To Library > Electrical and Instruments Section

If turning the ignition switch does not cause the starter to run, follow these steps:

Turn of ignition, put gearshift in neutral, pull up hand brake.
Open bonnet and locate starter relay.
On the started relay jumper the brown wire on terminal C1 to the white/brown wire on terminal C2, the starter should run. If not, you have a bad solenoid, or bad connection from relay down to the solenoid coil. If you hear the starter solenoid click then you could have a bad starter.

If it runs, then with ignition off, jumper brown wire on relay terminal C1 to the white/red wire on the relay terminal W1.

If the starter still doesn't run, then you have a bad starter relay. If it does run then I would suspect the ignition switch start contact, unless your car has a seatbelt sequential control system that is preventing the starter relay from activating.

MGB Starter Relay Circuit Diagram

— Checking the Starting Circuit —

Written by Gil Dupre – Created 2007-02-10 Published 2007-02-10
Contents © Copyrighted and published under the following terms:
Released under the terms of the CC Attribution-NonCommercial-ShareAlike 2.5 License

Did you find this article helpful? Rate it or ask a question below!

Return to the MG Experience > Electrical and Instruments Library for more interesting articles

Comments on "Checking the Starting Circuit"

Did you find this article useful?
Do you have a question or comment about this article?

Leave a rating or a comment below, and get instant reply notification via email
If you have a long question, or a question not directly related to this article, please start a new topic in the Discussion Forums

Member Comments on Checking the Starting Circuit ↵

Rated 10 out of 10 based on 1 ratings

2012-05-25 15:07:14 # 6179

Comment by Dan Bramble

Rating: 10/10

Previous owner of my new/old '70 BGT replaced the start relay and starter when she wouldn't start. Sold it to me 'as is'. Start relay was wired wrong. (ground to C1) Easy to diagnose with this article. Thanks Gil.

2015-03-19 20:49:19 # 24732

Comment by Andy Rose

My starter seems sluggish. In fact I seem to remember it would not engage and I would have to "push start" my midget. Easy to do but not desirable. I took out the starter and want to clean the brushes with fine sandpaper, like emory paper. Then I want to clean and lub the gear on the starter shaft that engages with the flywheel. There is also a spring that I guess is okay. What type of lubricant for the extension shaft and gear that slides to engage the crank?

2022-07-04 14:30:13 # 81775

Comment by Wal Parnel

Reassembling the starter installed. The chart of the starter wires are wrong connections?

2022-07-05 08:47:22 # 81780

Comment by Wal Parnel

Reassembling the starter installed. The chart of the starter wires are wrong connections?

2023-05-20 13:01:20 # 86680

Comment by Norman Nalepa

In the diagram. Where does ths the green/white wire terminate?

Want to leave a comment or ask the owner a question?
Sign in or register a new account — it's free