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1979 Mark V Electrical Gremlins & Updates....

Hi Bill,

I'm slowly trying to fix a few electrical gremlins on my recently-purchased 8000-mile 1979 Bill Blass Mark V. The power windows now work fine, and I've moved on to a power seat issue. The driver's side functions correctly in all directions, except none of the switch controls control the function direction they are supposed to control. This is true for both the 2 two-way buttons, and the four-way joystick. For instance, front tilt may instead cause the seat to go rearward, joystick forward may cause the seat to go down. It all seems quite random, and moving a switch in the opposite direction doesn't give the opposite function, but rather a different movement altogether. Needless to say, getting the seat in the correct position is like trying to play a memory game and recall which button does what. (The power lumbar on the side of the seat works fine) The passenger side works exactly as it should by the way.

So my thoughts have been that the motors seem to be all working as intended, and perhaps the issue is the switch itself getting it wires crossed, so to speak. Have you seen this before, and if so is the answer a new switch? Or is there a way the wires going to the seat motor could be plugged in wrong, like if the seat was removed for service and hooked up wrong? I see this can't happen with the switch design in the armrest, as it only connects one way. Can the wires to the seat motor attach in such a way to make this happen? I'm leaning towards the switch itself, even though it does function in an oddball manner, but don't want to throw money at an expensive switch until I have a second opinion.

On an unrelated note, in order to replace a power antenna that just broke on me, do I access it by removing the passenger front tire and front wheel splash shield? The motor still runs when I hit the switch but the antenna doesn't move on its own, so I'm thinking a stripped plastic gear or ripcord strip in there somewhere. Is there a rebuild kit for these like there is for the power window motors? This of course happened AFTER I recently lubed it...Murphy's Law!

Thanks again,

Jim Smithbauer
Interior Design Manager
The Lincoln Motor Company

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Hi Jim -

I have never heard of a power seat switch failing internally and causing all of the functions to still operate but in an incorrect pattern. The wire connections somehow could have been installed incorrectly however during some previous repair inside the armrest near the switch or at the seat drive motors and solenoids. Only a previous owner would know for sure what caused this or when it developed. I don't believe that the vehicle could have been delivered from the factory in this condition without being corrected by the selling Dealer and the original owner. As a first step, these above mentioned connections should be carefully examined and corrected if necessary as per the factory wiring diagrams and electrical plug wiring configurations. The possibility may also exist that an incorrect switch was installed at some point in time as these switches are known to fail. We can assist you with more advice, information or parts after you have investigated the wiring and switch type further.

The power antenna can be accessed for removal as you describe but full removal of the wheel well is not necessary as it is flexible and can easily be folded partly in order to gain access for removal of the antenna after enough bolts are removed. We do have parts available to service these antennas. In addition we can also perform this repair for you if the unit is sent to us.

If you would need wiring diagram information etc. please contact our office and mention your blog inquiry.

Sincerely,

Bill

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Hi Bill,

I have an 8700 mile 1979 Mark V with the 400 V8. I'm having an issue where it occasionally stalls and am looking to see where to start troubleshooting. I've looked through past related questions, but they seem to have slightly different symptoms. Here's mine

- Car starts easily when cold or hot (I follow the manuals advice of one full throttle depression to start from cold to set the choke, about ½ throttle when warm), leading me to think it is not an EGR valve

- Car runs, accelerates, and cruises fine, with only a slight hesitation until warmed up for the first acceleration or two after coming off high-idle.

- The car has stalled on me once warmed up under a few different scenarios, like when applying the brakes while turning, idling or creeping in slow traffic while the brake is applied, and shifting into drive or reverse while pulling into the garage after a drive. But in all cases the car was fully warmed at the time. In all circumstances, the car starts right back up easily with no smoke or anything unusual, leading me to rule out vapor lock.

- This happens very intermittently, maybe only twice per drive, and not every time I shift, apply the brakes, or turn. It's usually just fine.

- When it stalls, there is no rough running first, it just quits altogether as if the key was turned off.

- It's happened through a few tanks of 93 octane gas from different places, leading me to rule out old or bad fuel. (The fuel is fresh too)

- I haven't tried cleaning the carb with carb cleaner because it seems like the problem would be more consistent if it was carburetor or fuel filter related, but am guessing here...

The car still has its original plugs and wires, and I'd like to keep them if possible. My mechanic said the plugs look good, and were getting good spark the last time I had it serviced for something unrelated and asked him to see if it needed a tune-up.

Does this sound like it could be an ignition module or coil starting to go bad based on it's very occasional nature? Or perhaps something else?

Thanks Bill!

Jim

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Hi Bill,

I came across a previous question of mine from a while back and thought I'd give you and the readers an update of what the solution turned out to be. I've included the original question and your answer below the update:

I did purchase a new power seat switch, and installed it into the driver's door. The problem remained the same. Then I removed the driver's seat and guess what? The 6-pin wiring harness connector was installed upside-down. I unclipped it, flipped one side 180 degrees, plugged it back in, and the seat worked great! I was surprised it fit either way. Based on my car's low mileage, I wonder if it was misbuilt at the factory, or just the victim of a dumb repair. Either way, it just goes to show that it's sometimes the simplest thing...

Thanks for the advice.

Jim

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Hello Jim -

After reading the description of your latest issue, it would appear that a strong possibility exists that one of the electronic ignition components is indeed failing. They are well known to fail in this manner on a vehicle of this age. They sometimes stop working when heated and then restart immediately. Many had issues years ago on vehicles that were only months old. The carburetor also has critical internal and external control parts that can deteriorate with age and ethanol laden fuel. Your spark plugs and high tension wiring although original cannot fail intermittently and all at once. Still they are key components and are over 35 years old and are known maintenance replacement items. The coil and coil wire though are common spark carriers to all of the high tension wires and spark plugs. The ignition system and the fuel systems both need to be maintained up to par in order to deliver optimum service. That is why age is against the spark plugs and wires in my opinion.

Sincerely,

Bill