Weird electrical gremlin

Started by MPlayle, October 04, 2021, 08:46:30 AM

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Had a weird electrical gremlin pop up today on Miss Ruby.  I got in to go somewhere, pulled the choke and went to start the car.  When I turned the key to 'start', one high beam came on and the starter solenoid just clicked rapidly.  The one high beam goes out when the key is turned off.

The car ran fine yesterday when going with Bruce to a C&C in Wimberly, Texas.  I had it on the trickle charger overnight as usual and disconnected the charger before attempting to start it.  I did not notice if the charger indicated any issue before disconnecting it.  It showed fine yesterday.

Retrying a start just got a single click from the solenoid.

I plan to find the receipt from the battery purchase in April and take it out for testing.  Any other suggestions for what to trace for possible wiring issue?

I did put the headlights on relays back in May, when I upgraded to a high output alternator after the RM Spring Drives in Kerrville.

I just went back out to check the car for the battery receipt and the charger has already cycled back to "float" mode - indicating it thinks the battery is fine.  (I will still take it out to be load tested.)


Check your ground connections - both at the battery, at the body and at the engine - bad grounds will do all sorts of weird stuff
Complete failure at retirement

1989 Cooper Racing Green
2009 Clubman S
2014 Audi Allroad


I had a faulty battery do some wierd things too. 


Yeah, I second the idea of a bad ground(s).  Sounds like the starting circuit is trying to find a good ground with enough capacity to turn the starter - but not able to do so - and the result is it somehow is doing so through one of the headlight relays/wiring.   Whatever ground the trickle charger is finding is sufficient enough to charge at low very amps, so that's why that looks okay.

Of course the first things to check are the big battery to car body ground, body ground(s) to engine block, and then from there on...

Also, check the big positive cable from the battery up to the starter/solenoid. 
1988 Austin Mini
2002 MINI Cooper S
1992 Toyota LiteAce (JDM)
1997 Jeep Wrangler Sahara


It was a struggle getting the battery out.  The Group-26 battery we put in during the Spring Drives was a snug fit.  I will put a strap under it when I put it back in to make the next removal a bit easier.

The battery tested out fine at the nearby Autozone.  I have already pulled the fuses from the main battery terminal on the solenoid to the headlight relays and capped them with fingers from a rubber glove.  I will check/clean all of the grounds after lunch when I put the battery back in to test the starter/solenoid by itself.  Mine is the later style with the solenoid integrated onto the starter.

I still have a spare earlier style, but that will not help if it turns out to be the starter/solenoid.

Crawling under the car to check the main battery cable is going to make me wish I had some sort of "portable lift".  Unfortunately, being a rented apartment garage with basically no power makes even that an unlikely option.


I got the problem solved.  It was a grounding issue.

I unbolted the ground cable for the battery in the boot and it was a bit oxidized and dirty, so I thoroughly wire-brushed it to clean metal on all the bits and put it back together. 

I went to do likewise with the braided ground strap on the engine, but gave that up as a "lost cause" since it was attached parallel with the main engine steady from the engine mount to the firewall mount.  With the big horizontal brake booster, it is hard to get into those spots and the mounting bolts/nuts looked pretty rusty.  The braided strap also looked rather dirty and oxidized as well. 

Instead, I got a short (19") 4-gauge battery cable and made a new ground from the flywheel housing to the right inner fender to augment the existing braided ground.

The car started right up good and strong.  I then reconnected the headlight relays and retried - still worked fine.  I did note that the left high beam is indeed out.  The right is working properly, so the left is either the bulb or the wire from the multi-connector under the slam panel to the bulb.  I will track that down later in the week.

Now I get to reschedule to Wednesday the plans I had for today with the car.


Complete failure at retirement

1989 Cooper Racing Green
2009 Clubman S
2014 Audi Allroad


I "love" electrical gremlins  ...  ...  ...  NOT!

I got the missing high-beam solved as well today.  More connection issues - between a poor splice at the headlight bulb for the high-beam power and a bad multi-wire bullet connector for the same power, that line stopped getting power at the bulb.

I redid the splice with a heat-shrink butt-connector and replaced the multi-wire bullet connector with a spare I had and all is working again.