constant voltage unit

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Nov 20, 2011 | 10:21 AM

#16

gfw1985

Cranky Old Guy

Joined: Mar 2008

Posts: 3,562

Likes: 6

From: Raphine, Virginia

You can test the gauges with a 9v battery. Just apply across the terminals and gauge should go full scale(just long enough to test. If gauges are good and getting power, ground sending unit wire and gauge should again go full scale. With all three inop, it almost has to be lack of power to IVR, or IVR. Check as explained above. Grounds are important. Make sure firewall is grounded to block, lack of this can cause a lot of funny crap going on. I'm one of few that enjoy electrical problems, spent my whole life chasing them.

Nov 21, 2011 | 04:57 AM

#17

66fordoldtimer

New User

Joined: Oct 2011

Posts: 6

Likes: 0

no they have not but like in my earlier post been checked with 2 D size batterys and they show good

Nov 21, 2011 | 11:02 AM

#18

huckdeuceman

Senior User

Joined: Dec 2010

Posts: 400

Likes: 0

Well, I'm ''dumbfounded''..wish I could help but have no more idea's other than maybe taking it to a automotive electrical shop'' and see if they can run it down? most places won't charge you unless they fix it? and it really shouldn't cost too much? just make sure
the mechanic is an oldtimer! and know's how these old trucks tick!

Nov 26, 2011 | 09:24 PM

#19

292fan

Freshman User

Joined: Aug 2007

Posts: 45

Likes: 0

Hi all I know this is an older thread but I just used 63beaters advice and built a instrument voltage regulator; works perfectly

. Is there any protocol as to whether or not I can share his info on other Ford forums. Namely forums for Falcons and Galaxies? Don't want to step on anybody's toes but price is a common problem. Due credit of course would be given.
Thanks,292fan.

Dec 6, 2011 | 03:24 PM

#20

1972-34ton

Rabbit-Hole Researcher

Joined: Feb 2004

Posts: 466

Likes: 6

From: Middle of Ohio

Home-made gage voltage regulator still works

My home-made gage voltage regulator still works years later. This does an inexpensive job of replacing the CVR on the back of the dash cluster.

I do notice a minor warm-up time, but have not found the temperature compensation issue to be noticeable.

See https://www.ford-trucks.com/user_gal...&albumid=23629.
gallery for pictures and the schematic. I made mine with a 9v battery terminal, so I could remove it if needed.

I agree with the above post on adding a Transorb or TVS (P6KE18A) to protect the circuit, and a diode is always good. This is a common circuit on the internet with schematics available. (Look up 5 volt voltage regulator LM...) There are only a few parts, so anyone with the ability to solder should be able to put it together.

Reading up on Transorb(s) (TVS, TransZorb, snubbers, etc.) might be good for anyone interested in zap-proofing their vehicle. Especially if you want to plug in fancy new devices.

Last edited by 1972-34ton; Dec 6, 2011 at 03:31 PM. Reason: Added Link

Dec 10, 2011 | 02:12 PM

#21

William

Logistics Pro

Joined: Feb 2000

Posts: 3,565

Likes: 9

From: Sun River St. George

Gauges

If you have the sweep instrument cluster, there should be a black ground wire from the metal portion of the gauge cluster to a ground point on the brake/clutch pedal support. This wire is to short from the factory and often is broken during repairs like replacing light bulbs and speedo cables. I usually make a longer one to replace this. Weak grounds cause really wierd stuff.

Mar 3, 2012 | 10:02 PM

#22

briankanaga

New User

Joined: Mar 2012

Posts: 1

Likes: 0

+10 for "63beater".

These parts are at radio shack and if you know how to solder, you're in business.
Drill thru the tap-welds on the the bracket that mounts the CVU, and then rip the CVU off bracket -- so you have a clean bracket to mount this thing on. Drill hole to mount the assembled transistor/heat sink on it. I used connectors that matched the factor connectors (as he shows in pic). Works great so far! Cheap fix!