I am getting to the point of wiring in my 1980-86 F series gauges into my 52 F-7 truck. I have tried to gather as much relevant info I can up until this point so that I make as few mistakes as possible. I have had some information that has not jived with some other information.

I have been told that this little box lower left hand of picture may be what is called a CVR or constant voltage regulator. This seems to appear on all 80 -86 instrument panels and if this is indeed the CVR ( I am still guessing that this is indeed that ) than it drops the voltage of the gauges from 12 down to 5 volts.

Can someone here confirm that this is or is not the CVR and help me to better understand where I am at as far as needing this and how to place this within my wiring.

I am not using this printed circuit board ( or tape circuit board as shown above ) but instead have removed the gauges entirely from their original plastic holder so that I may use them within my original 1952 bezel.

Has anyone attempted to use this same deal on their truck and can instruct me on the best way to go about it? Maybe there is an earlier one that would be easier to work with, I see posts here made where guys have made their own but I am not overly electrically savvy so finding one pre-made from the junkyard or using this one might be the way to go for me. Thanks for all of your help

 

Ok scrap most of what I asked above, it will prob. never cease to amaze me how much info a person can find if he has hour after hour to do searches on this forum and the internet. This is indeed the CVR that I will need to use within my gauges.

I did not know that the circuit tape just snapped onto the CVR until I saw a picture of it on-line without the tape.

I still have some questions on how to wire this into my harness, I have one wire coming in from aftermarket gauges marked gauge hot wire ( I think )

Does this CVR need to be grounded somehow? Do these gauges that I am using need to be grounded somehow and how might I go about doing that?

I am surprised with these CVRs so plentiful in the scrapyards that people are not using this but instead are making their own. This CVR costs me nothing at the scrapyard and now that I know what it is I will get a few more when I am there today just to have.

 

I haven't looked these things very closely, but am pretty sure the metal tab on the unit needs to be grounded. And one of the other terminals is in, and the other is out. You can probably verify this by tracing out the circuit traces on your old 80-86 cluster.

The gauges do not need a ground. One terminal is the + regulated voltage coming into the gauge, and the other terminal on the gauge goes to the sending unit. The sending unit is actually the ground for the gauge. The sending unit's resistance varies, and grounds the gauge more or less, and that's what makes the needle read more or less.

The gauge voltage regulator does work well, but you have to realize the way it works is somewhat primitive by today's electronic standards. Like the discussion on your old 52 fuel gauge sending unit, this regulator actually works like a flasher. When you get this all together and start poking around with your voltmeter, you will actually see the voltage flashing up and down to the gauges. Sort of like the old 52 sending unit, the flashing rate of the regulator varies with the voltage level coming into the gauges. It "chops" the voltage up, to making the gauges read more consistent as the voltage on the truck will vary wildly between approx 11v(very slow idle with lots of accessories) to upwards of 14v(high rpm, little load). Your gauges would read all over the place if you didn't have something in there to keep it leveled out.

Also realize that this regulator is made for these factory type gauges only. Don't try to use it with a aftermarket type gauge that is made for 12v input. It also will not work on GM gauges or a Ford truck gauge made 87-up.

 

1930 Dodge, there is a lengthy thread in this forum regarding the ICVR and a replacement circuit for it. The tab does have to be grounded and if you go look at some of the earlier Fords (not just trucks) the ICVR had studs with push on connectors. Chrysler used a similar system for a while in their vehicles.

Franklin, the 87-88 trucks still used the ICVR and thermal gauges, it wasn't till 1989 Ford changed to the 12V gauges, which FWIW are very similar to GM gauges (gotta love those mid series changes).

 

Didn't know it was 89, thanks for that.

 

Here's a thread containing probably more info than you ever wanted on the ICVR. I wouldn't use a true ICVR in anything where I wanted a stable reading on the gauges. If you read the last page or pages you'll see that there is a good replacement in the form of a true voltage regulator that is easily wired up. I'm running that and I'm very happy. Here's a picture of it:



Edit: It was user error.

 

Gary, suffering from CRS? No link back.

 

Thanks for telling me, Bill. It is now fixed. I have a new mini iPad and was using that to do the posting. I've discovered that when you post a link the iPad doesn't highlight the http:// in the popup like a computer does. So, when I paste the URL into it there's duplication as the stuff in there doesn't get overlaid.

IOW, my bad.

 

To many high tech toys huh?

 

Lol. Not too many, just an old man learning - slowly. But wait - I'm not old. Not for another year when I'll be as old as you are now.

 

Thanks alot guys, I did see that ICVR thread but am ( or was ) trying to stay away because of the I .....I get CVR but what the heck is I.....I thought maybe it would confuse me as it pertained to something else.

I cant thank you guys enough, this old truck will be back on the road soon and with only 23 000 miles it could prob use a stretch on the pavement

 

I went to the scrapyard this A.M and got a bunch of the CVRs, looking closely ( more closely ) I do not think it needs to be grounded, it is screwed into the plastic instrument cluster case and that is it.

The terminals on it BTW are identical in fashion to a 9 volt battery, almost looks like one would go on it except I think its a bit too wide.

None of the gauges have a plus sign on them so I have no way of seeing which is the hot wire coming in and which goes to sending unit except another poster on another forum told me this and it makes sense to me.......It will make a difference witch wire is on the positive see if one post has a plus or minis or one is gold and one silver or look at the bottom of the gauge way the needle will move the way the currant will flow to make the needle move

Thanks for the tip on the ground for the gauges. Someone told me on another forum that they needed to be grounded but maybe he was referencing aftermarket gauges which I do know in fact do need to be grounded.

I kinda figured these were ONLY for these gauges but I did wonder if someone here could use them on their OTHER year truck since it seems the Ohms reading for these gauges seems pretty consistent during quite a few years.

 

Thanks again

 

Trust me, it has to be grounded

 

If you look closely you will see that the later one mounts to the plastic through a bare place on the printed circuit. The older ones grounded through the metal shell of the instrument panel.