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Fix For Dim 71 to 73 Mustang Dash/Instrument Panel Lights
#1
I stumbled accross a fix last weekend for my dim dash board lights.

A couple of weeks ago I installed some LED bulbs I bought off of ebay: Item title: 2 x T10 Super White 6-Led Light Bulb
Seller User ID: ushd

These offered some improvement, but still was not happy with the brightness.

The following week I noticed my charging system was not charging (this was a new problem and did not have anything to do with the dimness of the dash lights), so I had the Alternator tested at Autozone, but it was fine. I had a new Motorcraft voltage regulator and starter solonoid (just did the solonoid for looks really) so I begain the installation. In the process I took my Dremel tool with a wirebrush attachment and cleaned the mounting holes and screws for the regulator and solonoid. I cleaned all the ends of the wires that connected to both the regulator and solonoid, as well as the battery terminal connectors at the solonoid and where it grounds to the regulator. I also cleaned each connector at the back of the alternator while I was at it. It took some time and patience, but when all was reassembled I tested the charging system with a voltmeter and I was getting almost 14 volts at idle.

That night I started to take the car out for a spin and when I turned on the lights I could not believe how bright the dash lights were, including the radio, clock, lighter, wiper knob light, headlight knob light, and auto shift light. I'm not sure, but the wire that goes from the solonoid accross the shock tower mount support and into the firewall may be the clue. It's round connector was pretty corroded.

Here are some before and after pics of the solonoid and regulator and the associated wires. I took thses pics as a reference for reassembly. Try cleaning up all the connectors, holes in the fender, and screws. Remember to disconnect the battery first. Apparently one or all of these wires was the problem.

In this pic I outlined the area in red for the wire I believe goes through the firewall. Not sure what the rectangular thing is called that the wire connects to on the solonoid, but I spent a lot of time cleaning all the contact points on it. It may be the key to the brighter lights.

[Image: DSCF9376-1.jpg]

[Image: DSCF9456.jpg]
[Image: DSCF9454.jpg]
[Image: DSCF9455.jpg]
[Image: DSCF9457.jpg]
[Image: DSCF9458.jpg]

Mike AKA Ole Pony & Rare Pony

Our current Mustang garage/driveway
1973 Mustang Convert - Bought in 1974 - Still have it!
2004 Mach 1 Oxford White Auto, Bought Sept 06
2004 Mach 1, Azure Blue, Bought it Sept 09
2001 Mustang Bullitt - Dark Highland Green, Bought It Sept 29th, 07
[Image: 2chq68g.png]
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#2
Glad to hear your problem is solved! Good advice on cleaning electrical contacts also. A dab of dielectric grease on each connection will help keep them fresh for a long time.
[Image: 1gq8uo.png]
1971 Mach 1 - 306cid/C4 Bright Yellow
1972 Coupe - 306cid/C4 Gold Glow (in restoration phase)
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#3
EXCELLENT post, THANKS for sharing.

These are the types of posts that will undoubtedly assist others on their projects.

BT
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#4
Good post I'm going to look at mine now Thanks.
[Image: 20r9ylt.jpg]
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#5
And, I'd add, great pictures. Thanks for including those - they always make a huge difference!

Mark
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#6
I think that square box is a noise suppresor.

On the 71-72 it's a round canister tat mounts under the voltage regulator.

Cleaning corrosion is a great idea however even when the lighting is running optimal in our cars it's still very dim.

Use dielectric grease on all connections after cleaning so it will maintain the contacts.

I switched from bulbs to LEDs and my lighting quality went from a 2 to a 5 on a scale of 1 to 10

I'm always on the look out for something better.

I have removed my blue diffusers in the clusters as well.
[Image: sig.jpg]
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#7
(10-11-2010, 09:46 AM)72HCODE Wrote: I think that square box is a noise suppresor.

On the 71-72 it's a round canister tat mounts under the voltage regulator.

Cleaning corrosion is a great idea however even when the lighting is running optimal in our cars it's still very dim.

Use dielectric grease on all connections after cleaning so it will maintain the contacts.

I switched from bulbs to LEDs and my lighting quality went from a 2 to a 5 on a scale of 1 to 10

I'm always on the look out for something better.

I have removed my blue diffusers in the clusters as well.

My 73 also has the round canister under the regulator. It is the radio interference suppression condenser. I circled it in red in the picture below. I'll try to research further what the rectangular thing is on the solonoid.

[Image: DSCF9458-1.jpg]

Mike AKA Ole Pony & Rare Pony

Our current Mustang garage/driveway
1973 Mustang Convert - Bought in 1974 - Still have it!
2004 Mach 1 Oxford White Auto, Bought Sept 06
2004 Mach 1, Azure Blue, Bought it Sept 09
2001 Mustang Bullitt - Dark Highland Green, Bought It Sept 29th, 07
[Image: 2chq68g.png]
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#8
After researching the wiring diagrams that came with the factory Ford Service Manual set, it appears the rectangular thing on the solonoid is a 20 Amp Circuit Breaker. It is only used if the car has more than four electronic options. Mine probably has it because it is a convertible with the power top.

It would be interesting if anyone that has the circuit breaker on the starter solonoid post up and tell us what options you have. Probably all convertibles should have it.

[Image: DSCF9457-1.jpg]

Mike AKA Ole Pony & Rare Pony

Our current Mustang garage/driveway
1973 Mustang Convert - Bought in 1974 - Still have it!
2004 Mach 1 Oxford White Auto, Bought Sept 06
2004 Mach 1, Azure Blue, Bought it Sept 09
2001 Mustang Bullitt - Dark Highland Green, Bought It Sept 29th, 07
[Image: 2chq68g.png]
  Reply
#9
the rectangular box is the circuit breaker for the convertible top, the fat wire goes to the top switch. That thick wire may also have a pigtail that goes to the underhood light if that was an option on your car.
Be careful the positive on that wire looks awfully close th the ground nut on the solenoid.
Those are nice before and after shots, looks good
[Image: mustangnight010.jpg]
1972 Mustang Convertible 351C 4V
1966 Ford Galaxie 7 litre-4speed

Jorge
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#10
OLE PONY;2961 Wrote:I stumbled accross a fix last weekend for my dim dash board lights.

A couple of weeks ago I installed some LED bulbs I bought off of ebay: Item title: 2 x T10 Super White 6-Led Light Bulb
Seller User ID: ushd

In this pic I outlined the area in red for the wire I believe goes through the firewall. Not sure what the rectangular thing is called that the wire connects to on the solonoid, but I spent a lot of time cleaning all the contact points on it. It may be the key to the brighter lights.

[Image: DSCF9376-1.jpg]

[Image: DSCF9456.jpg]
[Image: DSCF9454.jpg]
[Image: DSCF9455.jpg]
[Image: DSCF9457.jpg]
[Image: DSCF9458.jpg]

Just to comment in on this,

That is in fact a circuit breaker, all cars have it regardless of the options installed, it's a 20Amp breaker, unless you have a convertible, then it's a 40Amp breaker. It doesn't have anything to do with the brightness of the dash lights. You can see the connector it runs too if you pull the drivers side kick panel. There is a yellow connector there that has three (3) female receptacles. Here, depending on what your car has installed in terms of options, is where you'll see two or three different plugs.

In most cars, this is for the Seat Back Lock Solenoids (at least in my 73, because the solenoids pull a large amount of juice for prolonged periods, they got their own independent circuit.

The power for the dash lights, all comes from the headlight switch. There's a large yellow wire leading into the switch that is the 12V source for the system, and then the front leftmost spade (when seated in the car looking forward) is the output to the dash cluster. With the lights on, and the dimmer set to the "on" click position, you want to see as close to 12V coming out as possible. This is going to drive your intensity more than anything. Even a little corrosion here can lead to a huge reduction in voltage and therefor brightness.
2013 Ford Focus SE Flex Fuel 5spd - Daily Driver
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