Fuel guage revisited

andy · Post by **andy** » Fri Jun 15, 2007 2:36 pm

I have the old guage out and a new one from SAV ready to go, but I have some questions,
1 On the back of the old guage on the lower left rear looking at it from the driver's seat there is a stud that had 3 brown wires coming off of 2 connectors. When I test the connectors with the ignition on a get 19 volts on the single brown wire and 0 volts on the double brown. Is 19 volts a good reading?
2 In the middle of the old guage was a plastic connector with 2 positions. One side had a red (violet?0 wire coming from it and the other had 2 black wires. With the ignition on the black wires read 20 volts. Is that a good reading?
3 Is the above mentioned red (violet?) wire the one that comes from the sender?
4 The new guage only has 3 studs on the bottom. There is no place for the place plastic connector with the two black wires and the red (violet) wire. Does this mean I am going to have to cut those wires from the black plastic plug?
5 The new guage has what looks like a downsized electrical plug on the back on top. I'm guessing this is for the light. Does anyone know exactly what it is for?
6 How do I know by looking at my 710M which schematic applies? The repair manual has two one for black out lights and on without. I'm asking this because the schematic for the wiries without blackout lights show breaker # 3 is not used. My # 3 has wires going to it. The point of that is I suspect my breaker # 6 may be faulty and if my truck doesn't use # 3 then I'm wondering if I could substitute # 3 for # 6 until I can get a complete set of breakers or do the swap like on the SDP websitee

Any help or suggestions anyone has will be greatly appreciated. Thank you

Andy

Jim LaGuardia · Post by **Jim LaGuardia** » Fri Jun 15, 2007 4:22 pm

Read the instructions first, I have installed these and they are a no brainer. (tan=ground to middle post , black to + , violet to sender signal) as for the breaker, #7 is the only one you can swap out, it is only used for the black out light.
The only Swiss schematic that is accurate is not in the manual, it comes in a pouch in the glovebox with the truck. I put a copy on photobucket last month.
Also if you look at the connector you pulled off the old guage, there are set screws to remove the wires(no cutting required).
Use common sense and disconnect the batteries prior to attempting to replace the breaker, replacements can be purchased from www.coldwarremarketing.com, or SAV(less than $20)

mjnims · Post by **mjnims** » Fri Jun 15, 2007 4:36 pm

Jim
Have the dealers found a source for the original breakers? Would be great to replace with originals in lieu of changing out to the marine ones. I have had no problem with the marine style breakers and have had them in one of my trucks for a couple years now but having the option for the originals would be good. I did the swap as the breakers being sold as replacements did not fit properly and were more like the mog breakers. I know Patrick CWR was having some made up but never heard for sure if that happened.

Again Jim is right on about the SAV fuel gauge swap. Just finished this a few weeks ago and it was very straight forward.

todds112 · Post by **todds112** » Fri Jun 15, 2007 5:44 pm

When you swap to the new fuel guage, does it show empty when it's empty, or is it the same as the factory one and would show empty when it's hit reserve?

andy · Post by **andy** » Fri Jun 15, 2007 7:20 pm

Jim, my instructions just tell me "+" Terminal = 24 volt, "-" Terminal = Ground, and ""S" Terminal = to sending Unit, and to adjust the guage after it is installed. I'm wondering how I'm going to get that little pot trimmer screw driver in the itty bitty hole after I have the wires on. My question was more related to the tan wires, if I ground the single tan wire then I'm putting 19 Volts straight to ground. In the little I can remember that isn't good. I found the little screw on the back of the double conncector and will remove the wires that way. Even putting a connector on them will be tight because there isn't very much slack in the wires to start with.

What did you all do to get power to the light on the new VDO gauge? I have two terminals that look like a small electrical plug.

I'm sorry about the dumb questions. While I was searching the archives on this there was one post that said the previous woner of that particular Pinz was under qualified to own one. Well, that hit home. But I've been under qualified before and I am capable and willing to learn. I learned and qualified on a 637 class fast attack submarine. So please bear with me if I have to ask questions. Thanks again very much for the information and your time.

Andy

Jim LaGuardia · Post by **Jim LaGuardia** » Fri Jun 15, 2007 8:40 pm

Attach the wires to the terminals as instructed. Each terminal is isolated. the guage will always read empty when there is 20L of fuel because the SENDER does not go to the bottom of the tank.
As for the light, attach one terminal to ground and reattach the original power wire to the other terminal. Most people pull the dash panel back to service breakers and guages, but disconnect the battery first.
One note, the tan wire (-) from the tab on the old guage must be connected to the center terminal, NOT THE HOUSING, if you fail to hook up as described the guage will always read full.

andy · Post by **andy** » Fri Jun 15, 2007 9:31 pm

Jim, okay I will do as you say tomorrow. Ahh.what happens if I pull the dash panel and DO NOT disconnect the battery?

Because that is exactly what I did today and the truck will not start now that I reconnected the old gauge. In other words what am I looking at fixing now that I have messed my mess kit? Thanks for your time and patience.

Andy

Jimm391730 · Post by **Jimm391730** » Fri Jun 15, 2007 11:21 pm

.what happens if I pull the dash panel and DO NOT disconnect the battery?

Probably you didn't zap anything, but the wires/crimps/terminals are pretty brittle after all those years. I've had wires break right at the crimp and crimps break away from the ring; you will have to look carefully, without stretching the dash much, to find if you have any broken wires or connections.

If you did zap things, they were shorted either after the breakers (in which case either reset the breaker or you killed it) or before the breakers (where you would have let the entire genie out of the batteries -- you couldn't have missed that!).

Best of luck,

Jim M.
712W and 710M

andy · Post by **andy** » Sat Jun 16, 2007 8:19 am

Jimm I kept the disconnect off and the ignition off until I needed to put the volt meter on the different leads. As soon as I got the readings I turned everything off again. There is a buch of brittle stuff and bent connectors back there. The wiring for the 360 degree flasher and the oil light were pretty bent. Breakers didn't look bad, I checked them because I am curious about my number six, it is either damaged or the reset button does not sit squarely in the hole. The spring portion of it appears to work. I'll be back on all of it in a while and will let you know how it goes, hopefully without too much more embarassment. Thank you for the insight.

Andy

andy · Post by **andy** » Sat Jun 16, 2007 7:20 pm

I got back on the guage today. I lengthened the three tan wires and put connectors on them. I also put a connector on the two black wires that go to the positive side of the guage. Dittos for the sender wire. All connections were covered with liquid tape.

I got rid of the two old Interstate batteries that were in the truck and added two red top Optimas almost exactly the way they did it on the SDP website. I did all the connections while the batteries were out.

A few questions: 1) I did not hook up anything to the light area of the new guage. The reason is the old light had two wires going into a, what I call spade connector, and from there to the socket which had rubber material around it. The question is: are both of these black wires hot? If so can I just connect both to one side of the prongs in the back and then just run a short piece of wire to ground from the other side? I don't see how one of the wires could be a ground to lets say the side of the socket if they both come of the same connector.

Does anyone know a good source for a reasonably priced battery equalizers? Aparently with 6 or 7 major auto parts stores and 3 or 4 boat dealers no one in Del Rio has them. The variety found on the web has too big a range in size and price for me to pick.

The truck started just fine and the guage actually moved to just above 3/4 which should be close to right. Once I use most of the fuel in the tank I will try to adjust the guage before I refill.

Many many heart felt thanks for your help Mr LaGuardia.

Andy

Jimm391730 · Post by **Jimm391730** » Sun Jun 17, 2007 11:59 am

I did not hook up anything to the light area of the new guage. The reason is the old light had two wires going into a, what I call spade connector, and from there to the socket which had rubber material around it. The question is: are both of these black wires hot?

The stock Pinz lighting circuit did not have the lights going directly to ground; they switched in a resistor to limit the brightness of the bulbs when the blackout lighting was active. One of the leads should have 24V when the light switch is turned on. Use that to the new bulb and you should have a functioning light (but it won't dim in the blackout positions).

Jim M.
712W and 710M

andy · Post by **andy** » Sun Jun 17, 2007 12:29 pm

Jim M, I will try that, but right now I think I have a bigger problem. The truck started beautifully this morning. I ran it for about 50 miles to go check some feeders at one of the ranches I feed. When I got back, the new Optimaswere hissing and there was condensation all over the inside of the box! I'm 99% sure that I wired them right, positive to negative, positive to negative. So, I'm wondering where to start looking now. I'm guessing maybe they aren't recharging, but I don't have a clue really. Thanks for the info on the light wiring to the guage.

Andy

Foz · Post by **Foz** » Mon Jun 18, 2007 9:39 am

Didja wire it like this?

Note the postive lead from the truck is marked +

You can visually trace the truck's minus lead to the battery disconnect switch.

andy · Post by **andy** » Mon Jun 18, 2007 9:58 am

Yes, the only change I made compared to what was in the SDP website was to the way the batteries were held in the tray. I also had to cut the tie wrap on the "red" lead and the longer black one so that they would stretch to the new position of the terminals. On the forward side of the tray I got the jumper in and tight to the posts also. I also posted more information under the topic boiled batteries. I wonder if Jim LaGuardia has ever considered moving his shop to San Antonio?