'74B - 23k miles
She wouldn't start but the starter relay "clicked" once. No change after cleaning all fuse box connections. I was ready to pull my starter for a rebuild or replacement of the solenoid when I consulted my "Your Expert Guide to MGB & MGB/GT Problems and How to Fix Them" by Roger Williams. There I found a trick where you put the ignition to run and connect the c1 and c2 starter relay wires together. She started right up.
My question, before I spend $40 - $80 on a new relay; is there anything else I should check? I know I'm dealing with Lucas electronics but I just can't see how a part with 23,000 miles could be bad.
The MG Experience ~ MGB & GT Forum ~ Archives
MG MGB and MGB GT Technical Talk
MGB & GT Forum: Starter Relay
Join the discussion, post your photos, or ask your own questions. Membership is FREE!
'74B - 23k miles
I dont know if that relay can be taken apart and cleaned but its not about the miles so much on electrics,
its the age and corrosion that takes its toll.
Dan there are three basic things to check: the starter, the relay and the ignition switch. You checked the starter...it works. Next put a test light on term W1 (white/red wire) and turn the key to 'start'....light go on? if yes and starter no workie...bad relay. Light not go on....check ignition switch connections. Check white/red wire at switch....if it goes on when you turn the switch to start.....check wiring from switch to relay. If no....replace ignition switch.
If you're refering to that switch that's mounted on the front inner fender just aft of the fuse block that has 4 wires coming off it, that can be taken apart and cleaned. Pull the relay and look at the bottom, it has little tabs that can be folded back. Pull those up and pull the insides out and you should have a set of points in there. Use some 320-400 grit wet/dry sand paper to clean them up with, get the loose dust out, reassemble and give it a go. I was having similiar symptoms and after cleaning that starter relay I haven't had any problems going on a year+ now.
Dan, I believe you can replace that relay with a generic one that will cost you $5 - $7 at the local auto parts store. Here's a link to a thread that will tell you how to hook it up.
Yeah, you can replace it with a generic parts store relay. Mine is the air-con relay for a 90's Jeep Cherokee (generic, $6), and the ignition relay is from the fog light system on 00's BMW (Bosch, $9, had an extra output tab I wanted).
You can buy a replacement relay in Radio Shack 30 amp automotive type and they are even made in UK --cost about 6.00 --been using them for a few years
Dan- I just went through this process. One of the first things I did was to purchase a four post starter relay at NAPA. Very inexpensive. It allowed me to verify that in fact there was nothing wrong with the relay. In my case it happened to be the starter switch in the column. The electrical part was fine, it was the mechanical part where the key mechanism turns the starter switch. The plastic had just fatigued and would no longer function. There is no warning with a failure like this. It's fine one minute and complete inoperable the next which makes it frustrating to diagnose. The starter switch and harness is not difficult to install. Your problem may be completely different but at least it will give you something to consider if you aren't able to quickly diagnose what's wrong.
If you're refering to that switch that's mounted on the front inner fender just aft of the fuse block that has 4 wires coming off it, that can be taken apart and cleaned. Pull the relay and look at the bottom, it has little tabs that can be folded back. Pull those up and pull the insides out and you should have a set of points in there. Use some 320-400 grit wet/dry sand paper to clean them up with, get the loose dust out, reassemble and give it a go. I was having similiar symptoms and after cleaning that starter relay I haven't had any problems going on a year+ now."
Agree about the generic relay, it's a cheap fix, and based on your description, there's a 90% chance that the problem is the relay. I picked up a 40 amp relay at Parts City, for $5. Don't be afraid of the wiring, as the relays come with a simple wiring diagram....To figure out the correct terminals, set your VOM to "ohms"...Touch the ground tab (clearly marked on the diagram),to the black meter lead, and touch the red to any other tab...The tab that causes the meter to go to "0" is the B+ from the ignition switch, the other two tabs go to the starter...(the ones you shorted when you tested the old relay). Hope this makes sense.
Advanced Auto parts - on the shelf, $7.79 with a mounting tab. made in the UK by Dorman. Installed two this weekend when my ignition relay failed. Just match the terminal numbers what you have to what you are installing and connect accordingly. 5 minutes, tops.
Well the cheapest fix is to take apart the old one and clean the contact points. Unless one of the lead wires has burnt or broken these units are very servicable.
Here is a pic of the inner workings. This one didn't work, ten minuites later it's a working unit now.
Thanks to everyone -- especially Dennis & Bill. I took my relay apart, cleaned and regapped the points inside and the old girl fired right up. And it only cost me a half an hour of work, a scrap of sandpaper and a few spritzes of electrical contact cleaner.
And just in time for a beautiful night ride.
I had the same issue with the starter relay clicking but no start. I've done alot of things in the name of saving a couple bucks, but I wouldn't have thought to open up the relay. Thanks to Dennis, Bill, and Dan, I sanded those 2 tiny, 37-year old contacts and the problem was solved without having to spend hours troubleshooting. Not to mention, I was able to walk out to my garage and get er done at a 11pm without waiting for parts. I love it when a plan comes together! Thanks for the pic too!
I tried this and appreciate the information. Mine did not work though. Any thoughts on a replacement unit.
I need to reconnect the the four wires. Which posts do they go on?
This is an archived discussion from the The MG Experience ForumsIf you would like to post a reply, please click below to visit the The MG Experience Forums:
MGB & GT Forum: Starter Relay
Archive Index | The MG Experience Forums | Return to The MG Experience