79 Hi beam shuts down one headlight

EvgO

New Member
Jul 5, 2022
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Hi all,
I'm new here and a new owner of a 79 notchback! Probably I am going to have a lot of questions in the future.

I have encountered my first issue and turn to the knowledge base of this forum.
I'll describe it in sequence.

When I pull the lights switch, both leftmost and rightmost headlights come on.
20220731_131509.jpg


When I pull it further, they come on brighter.
20220731_124113.jpg


When I pull the switch labeled "dim", all the headlights come on brighter, except the leftmost headlight.
20220731_124122.jpg

The dash also doesn't show that I've activate hi-beams.

What could be the cause and what would be the remedy?
Thanks!
 

General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
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I would start by replacing the headlight switch and checking the grounds in the headlight harness, they would be attached to the top of the radiator support with small screws. That one head light may need replacing
I realize you're halfway around the world from me but I would get a repair manual for that year mustang, something like a Ford Assembly Manual, check ebay.
 

EvgO

New Member
Jul 5, 2022
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0
1
I would start by replacing the headlight switch and checking the grounds in the headlight harness, they would be attached to the top of the radiator support with small screws. That one head light may need replacing
I realize you're halfway around the world from me but I would get a repair manual for that year mustang, something like a Ford Assembly Manual, check ebay.
Thank you for your reply!
I have a Haynes Automotive Repair Manual and 1979 Mustang/Capri Electric and Vacuum Troubleshooting Manual. Would you suggest I get a different one?
 

EvgO

New Member
Jul 5, 2022
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Those are likely good for the needs of a 'back yard' mechanic.
Is the car pretty much original?
I'm excited to learn to wrench a bit.
A few things have been changed - a remanufactured alternator, water pump etc, but it's been kept stock. The air intake is replaced by a DIY solution, but as far as I understand it's common on 2.3L turbos.
 

EvgO

New Member
Jul 5, 2022
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Well a turbo 2.3 :nice:
Extra points for that
Know anything else about the car? Was it imported for a dealer or an owner import?
Thanks, I'll need those points to get everything in order!

Don't know much. Previous owner was in Germany and put about 18k miles on it over 6 years. Total odometer reading is 90k km / 56k miles, which I think is great.
 

limp

wrap a little cheese around it and its a done
Oct 4, 2020
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Here are some pics from my 83 of the 2 ground wires on each side of my radiator..
Take them off, clean the bolt, connectors and metal where they are bolted to...
On my 83, both of these grounds go to a "cluster" of grounds soldered together.. I assume yours does too... Make sure this cluster ground is solid and is not coming apart.... I chased a grounding problem on a older Chev pickup that the solder was coming apart allowing the ground wires to have a poor connection within the soldered bundle.....
DSCF1087.JPG
DSCF1088.JPG
 
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EvgO

New Member
Jul 5, 2022
12
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1
Here are some pics from my 83 of the 2 ground wires on each side of my radiator..
Take them off, clean the bolt, connectors and metal where they are bolted to...
On my 83, both of these grounds go to a "cluster" of grounds soldered together.. I assume yours does too... Make sure this cluster ground is solid and is not coming apart.... I chased a grounding problem on a older Chev pickup that the solder was coming apart allowing the ground wires to have a poor connection within the soldered bundle.....
DSCF1087.JPG
DSCF1088.JPG
Much obliged, will check tomorrow!
 

EvgO

New Member
Jul 5, 2022
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Was busy running the government tech inspection. Gave me a month's pass due to several reasons; our government mandates obligatory yellow blinkers and the mustang has red. Only way I can go with red is to register it as a historic vehicle, which is it's own can of worms. They also didn't like the seat latches not keeping the seats in place. I've read the forums and people are split whether it should be like this, or shouldn't.

Regarding the lights.
Went under the car and sprayed all the wires I could reach with anti-corrossive spray. Couldn't get the headlight out, since the screws stuck tight... Will get WD-40 and try again.

The left headlight reanimated, however... When I turn the hi-beams, ALL the headlights start flickering after a minute or so. I gather it's the relay? I'm also not getting a hi-beam indicator on the dash. Or right turn signal indicator, for that matter.

Ahhh, :rock:
56k is barely broken in.
pics of the dog house (engine compartment) please.
Pics of the engine bay:
20220801_135135.jpg
 

limp

wrap a little cheese around it and its a done
Oct 4, 2020
2,896
1,736
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Did you clean your ground wires? Spraying WD 40 does NOT count.... I noticed an engine to firewall ground on your picture? Remove and clean it too, then reinstall.... Easy, no cost stuff first.....
 

EvgO

New Member
Jul 5, 2022
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Is that dryer ducting on the air cleaner inlet?
Duct taped in place, no less!
As far as I searched the internet, everybody seems to come up with DIY solutions for the cold air intake, since there are no reproductions available.
As soon as I sort out the stuff that makes the car illegal on our Latvian roads I'll try to manufacture something more robust.
 

General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
23,666
8,748
203
What makes you think this model came with a turbo?
The 1979 mustang did come from the factory with a turbo I believe but they have some distinct parts and I doubt someone would remove it.
If you plug in the vin number at foxchassis.com it may tell you if was actually a turbo model.
@FoxChasis may chime in here.
pretty nice mustang regardless :nice: