I've been working on a 1986 244 and trying to fix one problem at a time.

I recently posted a topic about the tach not working on a rebuilt cluster that I purchased and one suggestion that I got was to check the ground cluster that is in the center console of the car.

Well i did find the ground cluster, (there were like 6 wires all hooked together), and although they looked clean and tight I did go ahead and sand them well and reinstalled.

Now here's my question:

Before doing this I had a problem with the charging system.
At key on, the warning lights would sometimes light up and at other times I would get nothing but the oil pressure light.
Also, the car was not charging while I had this issue since the battery ended up dying on me due to numerous starts.

Also, the engine was pretty much running like crap.
I would have to crank the motor for probably 10 - 15 seconds before the car would even fire.
Then I would have to turn the key off......try to restart the car and usually on the third attempt it would sputter to life.
The car also would not idle well once it did start.
I would have to feather the throttle for a minute or two before it would settle into what I would call a rough idle.....basically shuddering a little while idling.

Anyway, after cleaning those ground points I now get all of the dash warning lights every time I start the car.
I've verified that the alternator is charging since I now get 14.1 volts at the battery posts with the car running.

Furthermore I only have to crank the car for maybe 3 or 4 seconds before it fires and starts and it then idles perfectly with no sign of shuddering or missing.

So what the heck did I accomplish in cleaning the ground connections in the center console?
What do those ground wires go to that would have made such a dramatic difference in how the car starts and runs?

Don't get the wrong, I'm thrilled that this simple task seems to have solved a lot of my problems but I'm just wondering what my superior mechanical skills actually accomplished. :-)

Thanks in advance.
Dave
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I dream of a world where a chicken can cross the road without having its motives questioned.

Dave, I'm hesitant to post(but when has that ever stopped me) because the thoughts in my head are you fixed an intermittent poor connection, but it wasn't the ground circuit for the cluster which helped your charging and lamp test function. That's because the ground for those things is not inside the car at all. It is that blue wire between the alternator frame and the bracket bolt on the block.

If you follow that circuit Phil says needs two sides, the way it gets back to the negative terminal of the battery is through the alt. It is the positive side it needs from the instrument cluster, when the key is on and the motor is not running. Same for providing the pre-exitation (D+) voltage to the alternator.

The result is great and not to take anything away from that, but if now you know exactly where the ground wire for the cluster makes its contact with the transmission hump sheet metal, you could lift it off and test with it completely missing. No doubt there will be some interesting results, which might be valuable to those who troubleshoot by symptom/cause tables, but I'd like to know if your lamp test function then stopped again, and your charging voltage disappeared.
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Art Benstein near Baltimore

I used to be indecisive. Now I’m not sure.

First of all, thanks for the replies....

Art, I really don't know which of the ground wires is the one for the cluster.
There are either 5 or 6 of them that are all grounded to the metal frame of the center console, by a single screw. I don't know what any of them are for, or where they lead to.

I did notice that there is another ground at the transmission hump, just to the right of the accelerator pedal. I did not clean this ground but I think I'm going to go out and do so within the next day or two. Again, I don't know where that ground goes to but I'm honestly thinking about cleaning all of the grounds that I can find after seeing the results I got earlier.

I don't know if I mentioned it in my previous post, but cleaning these grounds did NOT make the tach start working. It solved a lot of other issues but not that one.

I was also very surprised that the warning lights started working because I was planning on getting under the car and cleaning the blue ground on the alternator. I didn't even know that wire existed until you told me about it when I was having some problems several years ago.
Having said that, the cleaning of the grounds and the alternator now functioning could be nothing more that coincidence. As I said in another post, the alternator would sometimes function and sometimes not function. I'm just wondering if there was some corrosion on the ground or the exciter wire that finally worked itself loose.

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I dream of a world where a chicken can cross the road without having its motives questioned.

Ah!
You found out why it's actually more important to have a good ground than all the fuses, switches or an electrical loads you can muster into a piece of machinery.

Very simply put, the "ground side" is in itself is "the" complete half of the battery/electrical system. It's also the most neglected or less thought about due to its simplicity! It does move or shake, twist or pop to break.


In a true electron "theory" class in schools it is "said" that the electrons travel only in one direction. In the true sense of DC (direct current) it has to go out the negative side of the battery first and then travels back to the battery on the positive side.

Anything on the positive side of the circuits are like safeties, controllers or things using the energy. Each having a definite purpose or problem unique to itself.

It's starts the hunting because it's the way we think "naturally" to deal with a problem or problems!

In your case of inter relationships, the work you performed with that many circuits, all in one place, demonstrated the networks and its electrifying direction of operation, in a sense.
Some can make arguments to the contrary, which always exists, with other electro-mechanical types of tinkerers about our fair planet.

In a nut shell, that is all I should say.
To go any further, in my way of trying to explain things, just might make a suggestion appear on here that there is a "meat" head inside that decaying a nut shell too!

Just like a battery, it takes two sides to make a whole!

Ever tried to short the negative side using a wrench?

😋😋 Phil

Yep. Like a successful Divorce, and a great cup of Coffee...and old Volvo needs good grounds, too.

(Don't ask me how I found that out.)

B