Hi,
I'm rewiring my '53 F100 (not using a harness!) and after carefully labeling each wire and replacing it, I now have great bright lights (a good thing). The problem is, only the battery/charge gauge is working. The Temp gauge goes to the peg on the COLD side, and the Fuel gauge does nothing. Oil pressure pegs past 80. Some background - before rewiring, the TEMP gauge seemed fine.
The Oil Pressure gauge was pegging on HIGH just as it is now, and recently, the Fuel gauge had stopped responding at all. I disassembled the entire instrument cluster, and cleaned the gauges with electrical cleaner and cleaned the rear contacts. Checked each one with a 1.5 volt battery, and they all seem to respond. I replaced ALL of the wiring on the truck (including the sending unit lines and grounds). I suspected that the fuel float had frozen, but with the other gauges not working, I am not sure. I have the Ford shop manual ('53) and it seems to show 3 different schematics for the instrument panel wiring. In an old Chilton book, it mentions that if the Temp gauge goes COLD as mine is, that it is being grounded. The gauge seems ok (checked with battery), and the sending unit seemed to work before rewiring, so I am assuming that it's a wire or connection (ground) issue.
I bought automotive wiring of the correct gauge (went one larger to be safe to avoid a possible 'resistance' issue). I have the sending unit wires out to the sending units and the are ok -not grounding out (that I can tell) and have the power line coming off the ignition switch from the GA connector, as I thought it was when I started.
Again, all new wiring, and the gauges SEEM to work (when a 1.5 v battery is connected to them - as specified in the shop manual). I can't tell which post on each gauge goes to the power and sending unit from the schematics (they are different). The headlights, parking lights, and instrument lights are all working ok too. I am out of things to try... anyone have any ideas? Thanks!

 

I restored a 53 f100 about 20 yrs ago. Make sure you have installed a ground wire from the FRAME to the CAB; Then make sure there is a ground wire/strap from the CAB to the ENGINE. That should fix the problem. The ammeter only measures current.
The 53 wiring harness is unique as the Guage cluster used an oil psi GUAGE and an Ammeter vs idiot lites as on the 54 models. Also this was the last year of the 239 cid FLATHEAD engine. If you have a flathead , there are 2 temp senders!

Restogreen! (PS see the ride of the week; thats my current resto.)

 

Hi Restogreen,
Thanks for the suggestion. I will give it a try. I don't have the duel sending units - it's just a single (on a 6 cyl 215 cid engine).
Something else that MIGHT be a problem... when the ignition is OFF the TEMP gauge is right in the middle (midpoint of gauge between H and C). I've seen a few pictures of the gauges on the 'net and they SEEM to show the needle at H. From reading how the gauge works, I am thinking it SHOULD start at H (with no power) and then go to C with power and work it's way back towards H... I am thinking *MAYBE* the needle is "bent" - it is pretty flimsy, and we had some trouble getting the instrument panel out and it did get caught up in the wires a few times(!). With this in mind, I *carefully* bent the needle over to H and powered it back up and it went to FULL C again - I let it run for 10 minutes and it seemed to move up just to the C, but another interesting thing, when I pushed in the choke to slow down the idle, the needle moved slightly towards the cold side, and when I reved the engine a little, the gauge moved slightly towards H (very slightly). It's funny that NONE of the gauges are working - I suspect the fuel sending unit is bad, as it quit working awhile back (but I thought it could be the wiring - gauge seems ok). I did remove the fuel sending unit and varified that the arm moved freely and float was intact, etc.
The AM gauge shows C with the truck running and then with the lights on, it shows even MORE charge! (must be a great charging system, eh?). I ran the wire in FROM the voltage regulator through the gauge to the circuit breaker - but maybe I ran it through the gauge in the wrong direction, but then it seems like it would be showing discharge all the time, and then more discharge with the lights (which is correct, of course). Anyway...I am really frustrated with this, and as I said - don't know what else to try, but I'll give the ground-plan a try. Thanks again. If anything else comes to mind, I'd appreciate it. The lights are working GREAT - for the first time since I've had the truck, I have bright lights (white, not yellow), so it's a start. Thanks again!

 

2 more thoughts....

1) There is a voltage stabilizer that mounts on the back of the instrument cluster. The original 53's were 6 volt pos ground systems. Of course I converted mine to 6 v neg ground and polarized the generator. This did not affect the guages. I dont recall if you said your truck was 6 or 12 v? If it is 12v, then you can buy a converter to drop the voltage to the guage. I believe Dennis carpenter Ford has these as well as LMC Truck.com. AND not to leave out Classic Trucks (Formerly Obsolete Ford- OK City,OK)

1A) Add that if you do change to a neg ground will require a NEG ground regulator as well.
1b) DO NOT USE an 8v BATTERY. This is a bast--d fix to a perceived starting problem caused by small diam cables. Make your own using welding cable,

2) When you pull out choke or rev engine youspeed engine up and the regulator and voltage stabilizer should compensate for the increase to stabilize the guage readings
2a The other thought I had was that you may be completeing a ground path thru the choke cable!! Yes it connects the engine to the cab if there is no ground strap from the engine to cab (location near throttle linkage thru firewall.
JT- Restogreen

 

About the general electrical system. (And this is my opinion....) If you would stay with the 40 a generator (6v) and a new 6v battery the regulator will charge the battery correctly. (You will see about a volt increase at the battery with engine running ie: 7.3v. The fully charged 6v battery will actually measure 2.1 v /cell x 3 cell groups= 6.3 v!!!!

I am not a big fan of converting to alternators ie delcos. Like I said ,,, opinions are like rectums and everyone has at least one or related to one. (family tree).

Again you must establish a good ground between the FRAME to the Engine; then from the ENGINE to the CAB. Your battery grounds to the frame first due to its frame location.

JT- Restogreen

 

Hi Resto,
Man - thanks for the great info! First of all, so I don't forget, the truck is still all 6v (keeping that way!) with Generator (of course). I had been told to get an 8v battery as the truck has always started hard - ESPECIALLY when it's warm. Drive a mile or two and stop and it barely wants to turn over. I am rewiring everything in hopes of solving that problem as well. You mentioned the welding cable / battery/ground cable ... What gauge of cable/wire would that be?
After your last post, I ran a wire from the dash to the door and out to the block but didn't get any difference - taking off work early tomorrow and coming home and putting a bolt under the dash and another in the engine block with 10-12 gauge wire inbetween - to follow up on your first suggestion.
I also disassembled the gauges (removed the backs) and replaced them with some fresh cardboard - the original material was crumbling. The E side post on the fuel gauge was hanging in there LOOSE! I managed to find a heat-resistant washer large enough to use as a support for around the post and put it back together and stuck a 1.5v battery on it and it moved some, so HOPEFULLY, it's not dead. I did turn on the ignition after all of this and still nada on anything (no fuel, and temp still cold) - but tomorrow I will properly ground the dash as you recommended.
I also noticed that the wire coming into and behind the AM gauge comes in directly from the generator relay (first) and looking at the schematics (it's crazy - I have 3 different ones!) it looks like the wire should go through the circuit breaker / light switch first - but I'll check it out tomorrow too.
Thanks again - and thanks for the follow up. If you think of anything else to try - I'm all ears.

 

Hi Again,
Hey, you mentioned a VOLTAGE STABILIZER... I don't think I've seen that anywhere on the unit or in any of the schematics - is this a 12v-6v converter item (only), or something that I am 'missing'? Where should this be in the 'chain' or placement of things? When I get done with this (IF I ever get it straightened out) I should have some schematics to pass along so others won't have to go through this!
Thanks again for the great heads-up on the 8V battery - I had been fighting that for over a year (been told that by an older farmer that INSISTED that that was THE problem and it would fix everything!).

 

the voltage regulator is a small rectangle box of metal about 3/4 inch long and 1/2 inch wide

It mounts behind the dash, usually near the top. It has 2 spade connectors to it. Most wiring schematics do not show this thing at all believe it or not. You are supposed to naturally speak wiring chinese i guess.
Anyways, one of the wires from the gas guage connects to it. I can't remember where the other wire comes from.

Napa has these regulators for under 30 bucks-Ford dealers want over 75

 

I agree,check gauge regulator, if this truck has one ..it ouputs a constant voltage for all gauges. If you had an accidental short on any gauge power input terminal, that then runs to this, (they all do, jumped together and then to this, except amps)it is now toast...and no gauges will work. On "power in " side of gauge where this common wire is you should read a voltage coming and going when this works (average on 12 V cars is 5V, done by using 12 v , on less than half the time=5v average power). It may have to have case grounded to work..it usually snaps into a prong thing. Looks like a small horn relay, usually with two prongs. One side of it runs to feed all gauges, other side to ign on switch.I don't know about 6V trucks ,but I suspect it is 5V on them,,too. The destroyed fiber washers can be replaced by a kit from Harbor Tool, or maybe Digikey...I know I bought a kit of them..cheap, 1000's in there all sizes

On amp reading going up with lights, you are apparently running the wire from alternator or generator thru ammeter, which then reads only charging current, which goes up with lights on. That is wrong. The correct wire is the one that leaves start solinoid at battery terminal to power car; then curerent either comes or goes from battery...OK?? If "batt" wire also goes there from regulator, or output of alternator, (two heavy wires, one to reg or alt, one to car,) they need to be commoned up, and then one wire run from them, thru ammeter, back to batt term..got it? It must have been right from factory..what was changed?.. If factory stuff is there, Charge wire from alternator output has to go to what was A wire from generator, then (if no reg) jump batt and A at reg location..? Maybe all that has been removed, which is OK..Good luck, John

 

Hi JGrady,
Thanks for the info. I did get the AM working properly. I had routed the wire coming in from the voltage regulator through it - I think it had been patched in the past and not sure if it was correct, but it is now, and shows discharge and charge correctly!
As far as the gauge regulator - there isn't anything like it near the dash/instruments, but on the firewall, in the engine compartment, there is a horn relay and a starter relay (each with 3 prongs) that resemble the descriptions you guys have given, but nothing inside the cab or near the dash at all. I haven't checked the voltage coming in/out of either of them. The horn works fine - as do the lights.
I tried grounding the instrument panel to the engine block (and frame+engine) with no luck. I am thinking the fuel sending unit is toast, so that would explain the fuel gauge (does nothing). Today, I swapped out 4 different oil pressure sending units. The original (leaks oil and shows nothing!), and 2 NEW ones I bought from MACs awhile back, both show 80+ pressure - not quite pegged all the way, but very very close - well past the 80 mark - When I got the first one, I got that same result and Macs sent me a replacement, saying it was defective, but the replacement did the same thing - so I assumed that the truck/wiring was at fault. The 4th one, an incorrect unit from a 70's Ford Econoline Van, shows right near 80 (noticibly less than the others).
I found a replacement instrument panel (with gauges) on EBay, so ordered it, and should have it in a couple of days - so when that arrives, I'll hook it up and see what I get - that will eliminate (or verify) the gauges being 'bad'. I'm going to try to pick up a fuel sending unit Friday, and will put that in and if that registers, then I will be leaning towards the TEMP and OIL gauges being bad, unless it's the senders.
As I said - I am at a loss with this, as it's (seemingly) a pretty simple system. I checked the voltage on the 'power post' side coming into the gauge (from the ignition switch 'GA' post) and it's 6v. It sounds like there SHOULD be a regulator, but again, there never was one on there - and I haven't seen any in any of the schematics I've seen - but like I said - I've got 3 different schematics!
Thanks for the help. Keep me in mind if you think of anything else to try, ok?

 

Hey Restogreen,
Thanks for the advice - I grounded things as you suggested, but no luck. The rest of the details are in the prior post reply to JGrady. As I mentioned, I've got a gauge set coming it - but they don't know if it works (hah!). I'll try to get a fuel sender Friday and hook it up. If the fuel gauge works, then I can narrow it down to EITHER the TEMP and OIL senders or gauges, I guess. If the FUEL still doesn't register, then it's another issue. I mentioned that the power into the gauges comes off of the ignition switch (I'm replacing that also - just in case there is a problem there) GA connector and shows about 6v.
Thanks again for the help - and let me know if anything else comes to mind, ok? Do you know, off hand if the OIL SENDER is 6v / 12v dependant? The one of the 4 senders I have that shows around 80 is off a 12v (assuming) 70's Econoline Van. Just curious. By the way - nice green truck. I'm a big 'stock' fan - it looks just like you bought it this year...

 

Hey Snipa,
Thanks for the info. See my post replay to JGrady about the voltage regular please - is this what you are mentioning - or is there something ELSE I am supposed to have in the CAB, under the dash? The power to the instrument gauges comes right off of the ignition switch. There were 2 broken wires hanging under there and a LOT(!) of clother insulation and yards and yards of some sticky, and some mummified, electrical tape - a mess, so it's hard to tell how things used to be. The truck is definately all 6V still though (gen, starter, Volt Reg, Battery, etc).

Thanks for any info you can pass along!

 

53redford,

I have a 48 Ford tractor that was originally 6 volt positive ground that I have converted to 12 volts and negative ground. I'm may show my ignorance, but here goes! Was the 53 truck still 6volt when original? Was it positive or negative ground? If it was 6 volt, has it been converted to 12 volts? The AM read amps. It doesn't care whether 6 or 12 volts. The other gauges prabably do care. If it was 6 volt positive ground and is now 12 volt negative ground, the politarity of the guages are backwards. You may need to put a voltage reducer before the guages and possibly reverse the wires.

If I'm being dumb, just tell me! I have thick skin.

Good luck,
Danny

 

I think they used the regulator in 12 V cars for sure, effectively then using 5V, probably so as to keep the Ford sending units all the same..6 or 12V, they are running on 5V . Maybe originally they were designed for no regulator, @ 6 V? You may be missing that, the 6 to 5 v regulator, and is why your oil reads 80 lbs + (6.6 makes it read 25% higher than 5!) The problem with using no regulator and 6V is that most of them use heat to move the needle ,and heat goes as the square of voltage, so all the gauges will move maybe 5-8% as battery charges, and plus will read high all the time.. So some cars may have a 6V regulator, or not . Heat gauges do not care about polarity..they move slowly.3-4 seconds. Very old gauges have a coil of wire in them, and move fast, like a voltmeter, you can see fuel slosh in gauge etc..those will read backwards on reversed polarity..but I have not seen one in a car except before 1930.. But who knows? A quick crude attempt would be to hook by solder 2 or 3 1 amp radio diodes in series into the feed wire(1n4001 to 1N4007)(radio shack)..each one loses .7 V, so that will get your 6.6 down to around 5..put all the stripes the same way, (end)and stripe is away from + supply, or toward - supply.. 0.25$ , if you can't find regulator..gauges will move with battery voltage, but much better than where you are..There are still better ways involving Zener diodes, but too long to get into in post..try it! By the way, i tested my 58 gauges using these ideas, and all of them read at exactly 100% at 5VDC in..a good way to test and calibrate them..my pointers had been "fine tuned" (bent)by an animal.

 

the regulator is what was jgrady also mentioned. it is mounted BEHIND the dash panel back where the gauges connect to the instument panel. My 53 is converted to 12v, but it think a 6v still needs one, as these gauges all run on about 4.5 volts i believe ( and the voltage needs to be constant to these guages no matter what the idle speed is or if you are going 60mph)