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77 Marina keeps blowing rear lights

Posted: Fri Mar 01, 2024 6:56 am
by RemyNZ
Hiya I acquired a 77 morris marina off one of my mates. He had the car all legal then let it sit for 2yrs un touched. He couldn't get it started or anything so sold it off to me.

Iv since got the car running and driving nice but it keeps blowing the rear indicator and reveres bulbs. Also has no main head lights only one lamp works on high beam.

Horn, Front & rear park lights, break lights work also the front indicators work fine and haven't had issues. It's just the rears I'm having trouble with.

I had all the rear lights working for acouple days then when I tested it this morning they had blown again.

Would anyone have any idea on where to start, iv gone threw and tried cleaning and tightening up the connections. Can't keep burning threw bulbs

Re: 77 Marina keeps blowing rear lights

Posted: Fri Mar 01, 2024 8:34 am
by 1972TCCOUPE
Hi Remy,have you tested the voltage at the battery when it’s running? I would think a maximum of 14.7v. Anything higher than that could cause you problems. If it reads high you could have an alternator problem.

Re: 77 Marina keeps blowing rear lights

Posted: Fri Mar 01, 2024 8:49 am
by MarinaCoupe
The main problem with the rear lights on Mk1s & Mk2s is usually the earthing, as the units earth through their mounting bolts. If there’s much rust the connection will be iffy and lead to spikes in the supply. Try running an earth lead from the car body to the metal rear light unit.

Re: 77 Marina keeps blowing rear lights

Posted: Fri Mar 01, 2024 8:32 pm
by Mandator
MarinaCoupe wrote: Fri Mar 01, 2024 8:49 am The main problem with the rear lights on Mk1s & Mk2s is usually the earthing, as the units earth through their mounting bolts. If there’s much rust the connection will be iffy and lead to spikes in the supply. Try running an earth lead from the car body to the metal rear light unit.
Are those the pathetic springy jobbies (that pressed against the copper bulb contacts housed inside the rubbers) that press into holes in the Zinc body of the Light Cluster?
My first Marina 1976 reg had those and I was forever using fine abrasive paper to clean off the corrosion.
Problems always occurred on a cold wet winters evening, usually in a very dark location.
Boot open, Torch on - held in the mouth of course, or propped up against summat & guaranteed to fall over at a crucial moment. Lots of swearing and oaths to do the job properly the next day in proper daylight. Never did!

Re: 77 Marina keeps blowing rear lights

Posted: Fri Mar 08, 2024 11:40 am
by SLOW ITAL
, ,
i agree with the problems with earthing & bulb holders etc, or bad insulation which can blow fuses
but unless youv'e had bad bulbs, they tend to blow because of to high voltage, pointing to regulator in alternator as memtioned
by 1972tc coupe...thats my best guess
GIL...