Angie’s Blog

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Replacing the dash circuit board – part 1: Removal

The symptoms I was experiencing was a sudden and complete lack of functioning from my gauges one day while driving. I took my problem to the excellent guys at NAPA in Corvallis, OR and they said it sounded like a busted circuit board.

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Now, keep in mind that having dysfunctional gauges and having dysfunctional gauge lights are two different problems with two different sources. More about this later since I have to fix those too.

When replacing a damaged circuit board in the Mustang’s dash, you must first remove the dash pad.

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I looked up how to do this on Mustang Monthly and followed the pictures. Keep in mind that the Mach 1 Mustang they’re using isn’t exactly like mine. I didn’t have to remove a console because mine isn’t equipped with one.

However, I did have a terrible time reaching the screws above the radio. Even with a right-angled screwdriver I couldn’t seat the bit properly within the heads and resorted to use my fingers to loosen them. Luckily, they were loose enough as it was. I would recommend removing your radio if it’s after-market style and if you still have the removal tools. This will give you clearance to reach those screws if you’re unable to loosen them otherwise.

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Another problem I ran into was not only finding the three screws between the dash pad and the windshield, but once I located them, I realized the heads had rusted into a heap of powder. This was the most time consuming part of this whole operation because we had to remove them properly because you can’t just “rip” the pad out, even if you really want to at this point. To remove the screws we took two separate trips to Home Depot for specialty tools. The first set we tried was Grabit tools, in which the tips sheared off after 2 minutes of use. We went back for a set of Spiral Screw Extractors, which also didn’t work because they require a screw gun which chewed up my dash pad and didn’t make much of an impact on the screw anyways. We finally resorted to using a star-pattern screw bit and a hammer and hammered the bit into the screw head until it was embedded deep enough to grip. We then slowly loosened the screw, keeping the bit firmly placed in it’s newly made star-shaped hole.

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When hammering the bit, you must take all precautions not to hit the windshield in the slightest. Windshields aren’t designed to take impact from the inside and could easily crack if hit with a hammer.

Once this screw was removed, we were able to jiggle the dash pad loose and remove it. Since the circuit board in question is behind the dash cluster, you have to remove it as well. Mine was held in place with the minimal number of two screws. Once all screws are removed from the dash cluster you can slowly remove the cluster in one big piece. If you feel it still snuggly in place, check for wires or cables that might have snagged on the back of the cluster. My speedometer cable was still holding my cluster firmly in place.  We eased the cluster out a couple inches, enough to reach in and disconnect the speedometer cable from the speedometer head.  After that, you unplug the wire cluster from the back of the dash. This will be on the right hand side of the cluster and were the only wires leading to the dash. After the speedometer cable and wires are disconnected, the dash cluster came out easily.

Once the dash cluster was removed, it was easy to identify our problem. Two large bolts from the steering system had been wearing against the circuit board’s exposed plastic and had eventually rubbed away the plastic and had cut into the circuit paths themselves. The bolt had completely destroyed one path and had damaged two others, making it the obvious problem in this case.

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If, in a different case, you remove the dash cluster and see no obvious wear to the circuit board, try testing the voltage regulator and sending unit. An article blurb on this subject can again be found at Mustang Monthly.

Once it was obvious that the circuit board had to be replaced, I ordered a new one from Mustang Project and went about preparing my dash to be stored for a couple weeks while the part was shipped. You can reinstall the dash pad and cluster at this point if you want but it isn’t necessary. In Texas, the only component of the dash that you legally need to operate a vehicle is the speedometer. I carefully took apart the gauge cluster, bagged and labeled all gauge parts separately and stored them in a large tubberware with smaller tubberwares covering each gauge faces.

You don’t want anything placed directly on the gauge faces at this point because their protective plastic coverings are removed and the gauge face could get scratched or the indicator needle bent and broken. Store all parts away from animals and children, I opted for the cupboards above my washer in the garage so that again, nothing would be dropped or placed on top of the gauges while they waited to be reinstalled later. I removed all gauges from the cluster except for the speedometer. This I left intact so that I could reinstall it immediately. I took twist-ties and fastened the plastic cover and frame over the speedometer to protect it. I then took four screws and mounted the cluster section back into the dash, making sure to firmly reconnect the speedometer cable to the speedometer head.

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Once you have all the parts out, you can take a good look at everything to see if any parts need to be replaced. After pulling out my dash, I realized I had a small speaker mounted underneath. I don’t understand why since the sound would be buried under at least half an inch of continuous padding but after looking up similar dash pads for my year of Mustang I realized that the differences between my pad and regular pads didn’t stop there.

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This is also a good time to replace the plastic covers of the gauges if you can find some after market types. I noticed mine are scratched and clouded and would probably add a nice shine to the original dash if replaced.

To order a 1969 circuit board online, click here
To order the cheapest 1965-1973 dash pads I’ve found, click here
To order instrument bezel lenses, click here

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One Response to “Replacing the dash circuit board – part 1: Removal”


  1. Make love, not war!

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