If a 82 F100 did not have a tach option on the instrument panel, could one be added with only switching the tach in the cluster and changing the printed circuit board. Does there have to be a wire added off the coil or is this already there even if the option is not added to the truck?

 

The wiring is already there but you will need to get a different instrument panel, as the plastic on the back is not cut out for it.
Then it should be just plug and play.

If you or somebody else changed from a 4.9 to a 5.0, 5.8, 7.5 or the other way around a ground wire will have to be removed or added.

 

I didn't realize the 4.9 would be different from a V8. That doesn't matter the truck has a 4.9 in it and it is what came in the truck originally.

Thanks for the info on a new cluster would be needed. I did not know the plastic was not removeable.

This site is awesome. I'm always amazed at all the knowledge that can be shared here no matter what it is that you want to know.

 

The clusters are the same for 4.9 & V8, the wiring harness is different going to the plug. One is grounded and the other is not, this because that a 6 does not have as many pluses to the tach as a V8 does.

 

The only time you can't interchange, is if you do not have gauges now. If you only have idiot lights, then the alternator is wired differently.

 

Franklin, another question.


There is no tach and as far a gauges go the fuel and water have actual gauges, the oil and charge is just a light.

Is it possible to change the instrument cluster so it would have a tach and the fuel, water, oil, and alt were all gauges? Would it need a different wire harness or differtent alternator?

Is the alternator actually different or is the wires attached to it differently?

Would I have to look for one out a of a Xlt or something like that.

The truck has a 300 six in it, and everything is original.

 

You would have to have a different harness. The alternator is the same, it's just wired differently for the charge light.

 

Thanks franklin, thats what i needed to know.

 

I have found a place that I can get a complete wiring harness for under $12.

Now I know I need a different harness to convert my instrument cluster from idiot lights to gauges. It would be better to find a truck that has the same type motor (300 six) that has the gauge type I want and take every thing from it wouldn't it?

If I can't find one would the gauge cluster from a V8 and the wiring harness from a 300 six work together?

Thanks for your patients, I just want to make sure that I understand what I need so when I go I do it right the 1st time and don't have to go back.

 

You will have to look it over, I am not sure. The number of wires and their function will be close to the same, but the orientation between the six and the v8 is probably different. You may find for instance, the oil pressure sending unit wire might not reach if using a v8 harness with a six cylinder. See if you can scope it out at the junkyard.

 

Thanks Franklin

I think I'll take some pictures of what I currently have on the back of the cluster and in the engine compartment to take with me when I go. I know I'll get there and not be able to remember what I have.

If all else fails I guess I could live without the extra gauges and stick with the idiot lights and just upgrade to the tach. Would be nice to upgrade all of them at once though. Really want to have a factory tach though so I can tell more about where the motor is running at what speed.

 

Well I wish I would of did what I said I was going to do. Take a picture of the back of my cluster.

I went to the salvage yard to find me a cluster with a tach in it. Man are these things almost non existing? I must of looked at 25 trucks or better and only 3 of them actually had a tack in it. Most of them had all 4 gauges and no idiot lights though. I bought one that has the 4 gauges and the tach.

Bring it home and mine is not the same at all on the back. This is what came in my truck. I tought I could just take mine apart and put the tach in it and change the flexible circuit board and be done. Not the case. There is no recessed area in the back of it to attach the tach.



And this is what I want to put in it.



The one that came in my truck originaly has only 14 wires on the plastic connector that snaps into the back of the cluster and is located in a different spot. The one I bought has 18 wires.

Now for the questions. I really want to add the new cluster to my truck but don't want to change out the whole wiring harness if I can help it. I know I'm going to need another wiring harness to be able to hook up the cluster. Would it be possible to buy another wiring harness but use my exsiting wiring? By that I mean unhook the wires from the connector for my original cluster (leaving the wiring in the truck), plug those wires into the proper place on the connector from the harness I'll get from the salvage yard(once the wires are removed from it) and only add the additional 4 extra wires needed to go to the gauge cluster.

I know you guys have stated that the 300 six is wired a little different.
Will I be limited to the 3 trucks that had the tach option or can I also take the harness from the ones that had 4 gauges and no tach? I think this were I got confussed initially. Thinking that every one was already wired for a tach. I think you guys meant that if the cluster had all gauges and no tach that the tach could be added and it was just plug and play.

Not the case for mine.

I have a 82 ford service manual coming this week that should help me figure out some things.

 

Subford,

Thank you again for going the extra mile and calling me. The info was very helpful.

Steve B

 

Subford thanks agian for the info you sent me. When I went to the salvage yard I remembered you said that the 83 was the same as 82. That made me focus on the engine comaprtment and I noticed a difference in the 84 and up it had a lot more wires coming out in different places. Also it looked like it had a computer instead of a control module. I used the wiring diagram you sent me to make sure the harness was going to be correct. It matched perfectly. It took me about a hour and a half to get it all out, but it was worth it.

Now for the hard part, putting in the wires that are needed to make it all work.

 

I did notice something today that I'm not sure what to do about it. The alternator on my 82 truck has a plastic plug in on the side of it. The truck I took the wiring harness out of had 3 wires that attached on the back of it. I'm not sure what to do about this.

Do I need to change the alternator to make the alternator gauge work?