Gauge Wiring Question

[Lar4t9r]

1969 f100 with dash gauges.
Replaced the instrument panel voltage regulator which was shot. Tested all the gauges (except Amp Meter) got a pulse on all and when grounded, all pegged out. So all seems to be well. Next, tracing wires I found the bonehead P.O. cut off 3 of the 4 wires going thru the firewall thru the same hole. I identified these as the oil pressure sending wire (# 31 white w/ red stripe), coolant temp sender wire (# 39 red w/ white stripe), Ignition switch to coil wire (# 016A Pink resistor wire becomes # 16 –red w/green stripe to go thru firewall to coil) and what I think is a blue wire that is cut on both sides of the firewall. Hard to tell color as PO painted firewall both sides without masking wires. Anyway, I suspect it is #932 as shown on the wiring diagram, which would make it the carb throttle solenoid wire on a 6 cyl. w/ standard tranny. I have V-8 with auto trans, so I don’t need this wire (if I have identified it correctly). Can anyone confirm this for me?
Three (3) of the wires mentioned above (#’s 31, 39 and 016A) go into a flat 3 prong plug assembly on the cab side. My 2nd question is, can I use butt connectors to attach my sending units to the stub wires on the engine compartment side of the fire wall, or do I need to run new wires from the senders and the coil all the way to the flat plug? BTW, the coil wire is now spliced with a wiring nut ( the PO is obviously a genius).

I put the new senders on today and would like to get it wired up tomorrow. Any help on these questions would be appreciated.

[fordman]

so the wires are cut on the engine side of the firewall? if so you coul dsolder and shrink tube some extensions on the wires if they are long enough to hook onto. if they aren't you could cut the wires on the inside of the firewall and run new wires to where you cut it at. just to get a good connection. the throttle sensor wire i would ignore for now.

[Thunderfoot]

Gotta love some of those PO fixes…

On the single wire, that could be what you think it is and wont be any issue leaving it, or only other single type wire it might be for fuel gauge but it would be an Orange wire for that… Anyway I would see how it goes without it and go from there. (I have a 69 and will take a look at it in the daylight tomorrow and see if I have the same wire connection on the firewall for my V8 and get back to you on that)

On the gauge wires and ignition (coil) wire, you can but connect them together but it will be better if you solder and shrink wrap them back together. The crimp type but connectors will corrode over time and the connection will degrade and give you headaches later down the line.

[Lar4t9r]

Gotta love some of those PO fixes…

On the single wire, that could be what you think it is and wont be any issue leaving it, or only other single type wire it might be for fuel gauge but it would be an Orange wire for that… Anyway I would see how it goes without it and go from there. (I have a 69 and will take a look at it in the daylight tomorrow and see if I have the same wire connection on the firewall for my V8 and get back to you on that)

On the gauge wires and ignition (coil) wire, you can but connect them together but it will be better if you solder and shrink wrap them back together. The crimp type but connectors will corrode over time and the connection will degrade and give you headaches later down the line.

Thanks for the info Thunderfoot and Fordman, I'll solder them.

[dantheman71]

I can't offer any help when it comes to which color goes where right now because my wiring harness is in a box. I do want to put in my about wiring connections. I agree with soldering and shrink tube being a good way to keep corrosion out, but the thing I like better is to buy the butt splice connectors that are heat shrinkable. They are the same as a regular butt connector, only once you are done you put a heat gun on them and the ends seal up. I am an electrician and have used these connectors with a bit of tape on submersible water well pumps and have never had any trouble.

I am only suggesting this because if you have shakey hands like me, you hate soldering!!....and the shakes come from too many beers not too many electrical shocks
Thanks.

[Dragon]

A good shock 1st thing in the morning is better than coffee. Fellow Electrical contractor and engineer.

[Lar4t9r]

I soldered the sender wires at the firewall and shrink wrapped them and hooked up the new senders. Temp and oil gauges now working.

Next I need to tackle tail lights, brake lights and backup lights. All I have right working now is license plate light in the back. I have parking lights, headlights and emergency flashers working up front. All dash lights are working including the turn arrows when the emergency flashers are on. All fuses checked. I guess I'll start checking plugs to see where the power is interupted going to the rear.

Thanks for the help guys.

[Thunderfoot]

Good Deal!

If your License plate light is working then you are getting power to the back of the truck for the Tail Lights, as they use the same wire/power source. Check the bulbs and also the ground connection for the Tail Light housing (semi common problem) and see if you can get the Tail Lights working, with any luck all the rear stuff will work after that.

[Lar4t9r]

First the good news: Worked on the exterior lights off and on the last two days, finally got all working. Turned out that I had to run a ground wire from the frame to the left rear fender. Also, the green wire running from the front to the back was bad, so had to replace it. Cleaned up all the grounds, replaced one bad bulb and I now have turn sigs, tail lights, brake lights and hazards. Don't have back up lights 'cause I don't have the switch yet.

Now the bad news: However, in the process, I noticed that the dash gauges that I got working previously, now pulse at about a 4 second interval (fuel, temp and oil). This happens both with key turned on but engine not started and with the engine running, also in the accessory position. Will adjusting the cluster voltage regulator fix this pulsing?

I have not run the truck for several days until today, and had to jump it, guess I ran battery down running lights while I was working on the lights. Could a weak battery (or bad cell) cause this pulsing?

[Dragon]

Ouch pulsing get a multimeter and set the VR for 5 volts avg. Though the VR should switch faster than that.

Is the turn signal on at the same time? They are at about 4 to 6 second pulses.

[Lar4t9r]

Ouch pulsing get a multimeter and set the VR for 5 volts avg. Though the VR should switch faster than that.

Is the turn signal on at the same time? They are at about 4 to 6 second pulses.

Nope, that's without the turn signals. The pulse remains the same with the TS on or off. I'll whip out the multimeter and see what I have at the constant voltage unit and adjust to 5 v if necessary.

[Dragon]

A word of caution I keep thinking in my terms my 87V Fluke averages the pulse of the original types as they switch off and on the same way a turn signals does produce pulsing average of 5 volts. It probably is failing or is switching real slow.

I got a solid state one and am happy with it.

[Thunderfoot]

Your battery being real low will change your IPV output as it is in relation to the voltage of the battery... Charge up the battery first and see if the pulsing goes away, and adjust the IPV as necessary with the battery up to full voltage after that if needed.

Sounds like you’re making good progress!

[Lar4t9r]

Charged battery, but then gauges not working at all. Checked constant voltage unit, no power coming out, fried it somehow or it just went bad. Ticks me off 'cause I just put it on a couple weeks ago. Replaced with the solid state constant voltage unit and all seems to be well.

Next I am going to see if I can fix why it is running so rough. Tuned up w/ plugs, wires, condensor, cap and roter. Still rough. Didn't change points, looked good and just filed and reset. Guess I'll throw in the points and see if that does it. If not, I guess I need to start another thread in "Engines".

Thanks for all the help.

[Dragon]

Speaking of IVRs I can't get solid state IVRs anymore in NM. Does anyone have a link they could share?