Fix For Dim 71 to 73 Mustang Dash/Instrument Panel Lights

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Thanks Don...appreciate the input.
Hi any corrosion/rust/crude on or inside a wire/wire terminal will cause a voltage drop. Voltage is the engery to push the current. when a voltage drops occurs there is current lose. Remember these cars are wired in parallel with controlling elements in series (ie swt,cap,). In a parallel circuit each element will have 12 volts across that element and the current will be different across each element. In A series circuit all the elements will have a different voltage across that element however the current will be the same thru the entire series circuit.

 
I have a question regarding the thick black wire w/ silver hash marks going to the 20 amp circuit breaker. I believe mine is severed just outside of the firewall and there is no black/silver wire at the breaker. Does anyone know what this wire is for?

 
I think the breaker on my 72 is only in the feed for the windows - black with silver dashes. It has tach & ammeter. The breaker is mounted on a separate insulated stud which is also the alternator to loom junction, like on Jeff8877's pic.

 
Interesting thread with great info, and it makes me want to check out my issue when I have a chance, even though it's not a pressing one. I never drive my '71 Mach 1 J-Code 429 at night anyway, but the headlights work fine and even the headlight warning buzzer works. Surprised me one day when I heard that buzzer! The lamps in the front valance panel work fine but the ones in the grill do not at present. I believe one side just needs a new bulb and the other side needs a new socket (it used to work with some jiggling). All other exterior lamps work fine. It is a power window car and those work fine. I have no dash lights at all or radio (original AM-only), so I assume I should be looking at the connections to the headlight switch and the contents of the fuse box. I have played with the rheostat of the headlight switch but it has no effect on the dash lights. The automatic seat back release works fine as well. There is no bulb in the dome light and I'm thinking it wouldn't be working regardless. The car is such a blast to drive and I only drive during the daytime, so I never get around to things like this. But it would be cool to have dash lights and radio working, even if the dash lights are a little dim.

 
Big THANK YOU to Ole Pony for the post. I'm following suit and cleaning up the wiring in this area as well. Super helpful ideas from several of you on this post. Here is how mine looks after the cleanup. I found that an art brush worked well to apply the dielectric grease.

ElectricalCleanup.jpg

 
Last edited by a moderator:
Folks,

Another great way of making your dash and headlight brighter is to install a headlight relay. Your headlights pulls juice through the instrument cluster and this keeps the headlight power going straight to the battery. It's an easy install that takes 1-2 hrs depending on how anal retentive you are on wiring.

I also removed the blue defusers. LEDs are good but generally don't allow you to dim the lights (may or may not be a big deal). You can get blue LEDs which look pretty close.

KR

 
Folks,

Another great way of making your dash and headlight brighter is to install a headlight relay. Your headlights pulls juice through the instrument cluster and this keeps the headlight power going straight to the battery. It's an easy install that takes 1-2 hrs depending on how anal retentive you are on wiring.

I also removed the blue defusers. LEDs are good but generally don't allow you to dim the lights (may or may not be a big deal). You can get blue LEDs which look pretty close.

KR
Great advice! I have the headlight relay kit (p/n 11653-1A) from National Parts Depot), which I'll be installing in the very near future, after having had to drive home in the dark a few weekends ago. Not only were my headlights aimed as poorly as Marty Feldman's eyes, they were little tiny puddles of yellow on the ground not very far in front of the car - on High Beam! I also picked up some H4 headlamp housings from CJPP (p/n HLA1H) and some G.E. Silver Star bulbs from O'Reilly Auto Parts (loved 'em in my '97 Ram).

I also went to The Mustang Project and ordered their LED dash light replacement kit (p/n MP-7173-LED-GA-WHITE), along with the kit for the center 3-gauge cluster (p/n MP-7173-AUX-WHITE). Does anybody know where to score a new instrument cluster voltage regulator - just in case that's the whole problem?

I'm thinking correcting the headlight power issue, with the new H4 bulbs, actually aiming the headlights, and the LEDs from Mustang Project should have me seeing a lot more than just the faint outline of the gauges and just a couple puddles of road immediately in front of my car.

Hopefully, the clock/tach conversion gauge I finally ordered from The Rocketman will show up soon, so I only have to pull the dash apart once. ;)

 
There's been a lot of advancements in LED technology and applications. I'm researching OEM look LED headlights.

They will save a lot of amperage so I can use that for the fuel system and EFI without changing the alternator.

 
On my gauge cluster I have one bulb on a wire that goes into the cluster then 12 others that are twist and connect on the ribbon.  What is the ine with the wire all about ?

 
On my gauge cluster I have one bulb on a wire that goes into the cluster then 12 others that are twist and connect on the ribbon.  What is the ine with the wire all about ?
That is probably your alternator indicator lamp.  Should be two wires, both red/green, IIRC.

 
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.

DSCF9376-1.jpg


DSCF9456.jpg


DSCF9454.jpg


DSCF9455.jpg


DSCF9457.jpg


DSCF9458.jpg
 
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.

DSCF9376-1.jpg


DSCF9456.jpg


DSCF9454.jpg


DSCF9455.jpg


DSCF9457.jpg


DSCF9458.jpg
 
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.

DSCF9376-1.jpg


DSCF9456.jpg


DSCF9454.jpg


DSCF9455.jpg


DSCF9457.jpg


DSCF9458.jpg
 
I believe the rectangular unit on the forward side of the starter solenoid is a voltage regulator for either the convertible top electrical or a/c electrical…I’m sure other members will provide correct answer if I’m wrong, but only seen it on convertibles with air conditioning…it was on mine. I did replace all the tungsten bulbs with LED except the turn signal bulbs, and chose white because the blue plastic bulb domes in the cluster were fine, and very bright dimmable illumination was quite the difference for everything with a bulb, including the center stack guages…
 

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