Electrical gremlins NEED help.

[Carolina_Mountain_Mustangs]

Ok trying to gte my 73 original vert ready to take to a local show for mustangs next weekend on the 19th. This car sat for 25 years and po had hacked the wiring to pieces adding MSD, burglar alarm boom box with 2 amps, radar detector, went from no gauge to gauge. So the harness was a mess. So after much searching I did find a harness for this car. 351 C auto, gauges, tach, air, convience group, convertible. 

So I pulled the dash and went through the harness cleaning every connection with steel wool or a stainlees brush. Every ground was to bare metal. I got the entire harness including lights and engine. I got it all back together and it blows fuse # 6 which the Ford manual says is for stereo, turn signals and back up lights, 15 amp fuse. I get no fire to turn the engine ever. Nothing when you turn the key. The turn signal switch is a NOS Ford unit that I also replaced. Odd thing is that the radio buzzes and is on with the fuse blown. The other odd thing is when you hook up battery the right turn signal blinks does not matter if the lever is on or not and the fuse is out of the slot for turn signal.

THIS OLD GUY NEEDS HELP, LOL. Where do I look? Before I put the harness in I went over the harness and wrapped it again. No splices not cut wires all grounds are there and clean. Where do I go first? The po did change from fmx to C4 and never got the right lock rod for transmission. Do I need to jumper something to clear out the safety switch? I am lost when it comes to the wiring diagram. If it was on one sheet maybe but the multiple pages I am lost.

The big thing I do not understand is the right turn signal all the time key on or off, and nothing to the engine will not turn over. The MSD did not have the tach adapter when I got so I ordered one and wired as they show for a + connection on a tach which is what the Ford manual shows. The car started and ran before I put the unhacked wiring in but the gauges had got so hot they melted the center cluster just short or a fire and the tach did not work.

 

[boilermaster]

Carolina mountain mustangs,

regardless of weather the turn signal fuse is in there or not you still have power at the turn signal switch thru

the brake light circuit .

the ignition has to be on for the turn signals to operate, the ignition does NOT have to be on for the brake light circuit to work.

could be as simple as a shorted filament in one of the rear bulbs.

Boilermaster

 

[boilermaster]

Carolina mountain mustangs,

What shifter do you have ?

Fmx uses neutral/ reverse light at the shifter and C4 has switch located on the transmission shift shaft.

is it possible that you have BOTH and one is not even plugged in ?

Might not hurt to remove the shifter cover and see what is in there.

Did you adjust the neutral switch ? or chek to see if you had power there with the key on ?

                Boilermaster

 

[midlife]

The fuse for the radio, turn signal flasher, wiper shut-off, backup lights is the top-most left fuse, Fuse 1. Fuse 6 is for RUN-only things, mostly seat-belt warning, and master cylinder indicator lamp.

See if you can jiggle the shifter, as perhaps your NSS is out of adjustment. If still no go, put it in neutral and hot-wire the car to see if it runs. I interpret your message to mean that you cannot get the starter to engage.

Also, be aware that the headlight and alternator harnesses must be swapped out for tach-configuration when the conversion was done from standard to tach.

 

[Carolina_Mountain_Mustangs]

Carolina mountain mustangs,

What shifter do you have ?

Fmx uses neutral/ reverse light at the shifter and C4 has switch located on the transmission shift shaft.

is it possible that you have BOTH and one is not even plugged in ?

Might not hurt to remove the shifter cover and see what is in there.

Did you adjust the neutral switch ? or chek to see if you had power there with the key on ?

                Boilermaster

Thanks for the ideas of where to look.

Not sure on the shifter type but it is open now so I can probe the wires and see what is there. I did try having shifter in different locations but did not get any fire. I did notice there was a lot of wires coming to a curved switch under the shift indicator. Will check that this morning.

If the shifter is for the FMX what tells me that? I did see a Ford # on the switch in the shifter. I will also look for the switch on the transmission shift shaft. Thanks for giving me so ideas.

On the bulb short what do I look for there? I did clean all the sockets, grounds and bulb ends when I rebuilt the tail lights.

I was looking through parts and found another shifter that I bought that was said to be for C-4 it does not have the switch on it. I figured it had been removed. It does have the indicator light and wire.

I did check to see if all the plugs were connected going down to the transmission yesterday. Seems like there were three connectors that were square with probably 4 wires and on that was two wires. All were plugged together. These are the ones located on the left rear of the engine near the firewall.

I will have my coffee and breakfast and head out to see what I can find. I will let you know.

 

[Carolina_Mountain_Mustangs]

The fuse for the radio, turn signal flasher, wiper shut-off, backup lights is the top-most left fuse, Fuse 1.  Fuse 6 is for RUN-only things, mostly seat-belt warning, and master cylinder indicator lamp.  

See if you can jiggle the shifter, as perhaps your NSS is out of adjustment.  If still no go, put it in neutral and hot-wire the car to see if it runs.  I interpret your message to mean that you cannot get the starter to engage.

Also, be aware that the headlight and alternator harnesses must be swapped out for tach-configuration when the conversion was done from standard to tach.

Midlife, my seat belt warning buzzer works and no fuse in #6. I was going by what is in the Ford shop manual #6 was listed as turn signal, flasher, wiper.

I will probe the solenoid I am pretty sure I have fire to the small terminal on it. I will short across and see if starter kicks in. Can you describe the difference between harness on alternator for tach? I got the entire harness under dash engine and lights when I bought it.

Thanks for your info you need to live closer to mountains, lol.

 

[OMS]

Carolina mountain mustangs,

What shifter do you have ?

Fmx uses neutral/ reverse light at the shifter and C4 has switch located on the transmission shift shaft.

is it possible that you have BOTH and one is not even plugged in ?

Might not hurt to remove the shifter cover and see what is in there.

Did you adjust the neutral switch ? or chek to see if you had power there with the key on ?

                Boilermaster

Thanks for the ideas of where to look.

Not sure on the shifter type but it is open now so I can probe the wires and see what is there. I did try having shifter in different locations but did not get any fire. I did notice there was a lot of wires coming to a curved switch under the shift indicator. Will check that this morning.

If the shifter is for the FMX what tells me that? I did see a Ford # on the switch in the shifter. I will also look for the switch on the transmission shift shaft. Thanks for giving me so ideas.

On the bulb short what do I look for there? I did clean all the sockets, grounds and bulb ends when I rebuilt the tail lights.

I was looking through parts and found another shifter that I bought that was said to be for C-4 it does not have the switch on it. I figured it had been removed. It does have the indicator light and wire.

I did check to see if all the plugs were connected going down to the transmission yesterday. Seems like there were three connectors that were square with probably 4 wires and on that was two wires. All were plugged together. These are the ones located on the left rear of the engine near the firewall.

I will have my coffee and breakfast and head out to see what I can find. I will let you know.

David if the shifter has a switch in it, that is the switch for an FMX

The C4 and C6 nuetral safety switches mount on the side of the transmission

Here is a pic of the FMX switch

 

[Carolina_Mountain_Mustangs]

Carolina mountain mustangs,

What shifter do you have ?

Fmx uses neutral/ reverse light at the shifter and C4 has switch located on the transmission shift shaft.

is it possible that you have BOTH and one is not even plugged in ?

Might not hurt to remove the shifter cover and see what is in there.

Did you adjust the neutral switch ? or chek to see if you had power there with the key on ?

                Boilermaster

Thanks for the ideas of where to look.

Not sure on the shifter type but it is open now so I can probe the wires and see what is there. I did try having shifter in different locations but did not get any fire. I did notice there was a lot of wires coming to a curved switch under the shift indicator. Will check that this morning.

If the shifter is for the FMX what tells me that? I did see a Ford # on the switch in the shifter. I will also look for the switch on the transmission shift shaft. Thanks for giving me so ideas.

On the bulb short what do I look for there? I did clean all the sockets, grounds and bulb ends when I rebuilt the tail lights.

I was looking through parts and found another shifter that I bought that was said to be for C-4 it does not have the switch on it. I figured it had been removed. It does have the indicator light and wire.

I did check to see if all the plugs were connected going down to the transmission yesterday. Seems like there were three connectors that were square with probably 4 wires and on that was two wires. All were plugged together. These are the ones located on the left rear of the engine near the firewall.

I will have my coffee and breakfast and head out to see what I can find. I will let you know.

David if the shifter has a switch in it, that is the switch for an FMX

The C4 and C6 nuetral safety switches mount on the side of the transmission

Here is a pic of the FMX switch

Don,

That switch is there so I guess I should remove and not plug that in and use one on the transmission. I do not know if it is there have to check and see. Thanks for the pic.

 

[Carolina_Mountain_Mustangs]

I got under the car and there is not switch on the linkage to the transmission.

When I turn the key on I have voltage to the solenoid but when I turn key to start starter will not engage. When I short between the solenoid and battery starter turns engine.

So if I were to jumper the switch for the transmission or shifter should the car start? What terminals do I jump on the connections?

I have another convertible with gauges sitting right by this car so I can check the alternator wiring when I go back, it has a C-6.

 

[73pony]

I believe on the FMX switch you jumper the R-LB (Red & Light Blue) for the NSS.

 

[Don C]

David, I would do two things, make sure the NSS is connected before trying to jump it. An alternative would be to pull the square connector apart (at the back of the engine, not easy) and jumper it there, as Jason said the red/light blue wires. Before cranking it I would also check for voltage at the coil, with the key on.

I know what you mean about the multiple pages on the wiring diagrams, and following the circuits from page to page. I have printed and taped them together for complex circuits. For the most part the '71 circuit diagrams, for related items, are on one page and much easier to trace than the later year diagrams. These are fairly accurate for the basics for all years, and all years have the same color codes. When a question arises about '72s or '73s I always start with the '71 diagrams.

 

[midlife]

I got under the car and there is not switch on the linkage to the transmission.

When I turn the key on I have voltage to the solenoid but when I turn key to start starter will not engage. When I short between the solenoid and battery starter turns engine.

So if I were to jumper the switch for the transmission or shifter should the car start? What terminals do I jump on the connections?

I have another convertible with gauges sitting right by this car so I can check the alternator wiring when I go back, it has a C-6.

You have 12V to the S terminal when key is in RUN position but the starter doesn't engage, but yet when you short that terminal to the battery post, the starter does engage?  That tells me that you have defective wiring or a massive resistance in the NSS/crank wiring, as with no load it reads 12V but with any sort of a load, it drops to near zero volts.

As far as the alternator harnesses being different for tach and non-tach, the voltage regulator wiring needs to change depending upon whether you have an ammeter or an alternator indicator lamp.  One system requires all four pins on the VR; the other only three, and two of the wires get located differently as well.  I can't remember off-hand which system is which.

 

[Don C]

Maybe the "I" and "S" wires are reversed and the "I" wire (red/light green) does not carry enough voltage after it passes through the resistor wire to the coil to activate the solenoid. The "S" wire is red/light blue.

 

[Carolina_Mountain_Mustangs]

I took a break from the wiring. Got drive shaft back in and buttoned up.

I will go down after lunch and jump the nss and see what happens and do some checks Midlife suggested. I was pulling the bulbs out of tail lights and checking each one to see if ok when I stopped for lunch.

 

[boilermaster]

UM,

Pretty sure that one should have battery voltage at the S terminal of the starter relay when the key is in the CRANK position and only when the crank position.

If one looks at the FMX switch that OMS posted, you want to jumper the 2 red wires at the very top of the photo.

One of these 2 wires should get battery voltage when the ignition switch is in the crank position and the other should provide battery voltage to the S terminal of the starter relay when ignition switch is in the crank position.

 Might actually be easier to do your jumpering at the park/ neutral switch at the shifter, at least you will have a free hand to turn the ignition switch.

 Boilermaster

 

[Carolina_Mountain_Mustangs]

UM,

Pretty sure that one should have battery voltage at the S terminal of the starter relay when the key is in the CRANK position and only when the crank position.

If one looks at the FMX switch that OMS posted, you want to jumper the 2 red wires at the very top of the photo.

One of these 2 wires should get battery voltage when the ignition switch is in the crank position and the other should provide battery voltage to the S terminal of the starter relay when ignition switch is in the crank position.

 Might actually be easier to do your jumpering at the park/ neutral switch at the shifter, at least you will have a free hand to turn the ignition switch.

 Boilermaster

I had to call it quits for today. My back will not let me do anymore today. Hot shower and try to rest it some and will get back to this tomorrow. I do hope the nss is the issue I hate wiring in cars. Home is nothing. I worked for Square D and Cutler Hammer for about 20 years and I cannot read a wiring diagram, lol. I built their prototypes and tooling but to heck with electrical.

Thanks guys for all the suggestions and keep thinking my brain is dead, lol.

 

[Carolina_Mountain_Mustangs]

Latest on electrical.

I tried probing the two red wires on the nss under the shifter. They never have current to either of them but when I shift out of park the seat belt buzzer goes off as it should.

I then went under the hood and unplugged the nss and jumped between the two red wires there and engine will still not crank with key.

I went back to solenoid and shorted to the + battery and engine cranks.

I did pull all the tail light bulbs and checked each one no issues. The right turn signal stopped blinking all the time but now the tail light on right stays on all the time. Key on or off.

With my limited knowledge in the electrical part of these cars I do not see anything I can do but take it all apart again and go back together, dash out everything. All the plugs are fool proof so I cannot see how I could have anything wrong there.

The first area I am going to take out is the new turn signal switch. When they come, even NOS Ford, you do not get the connector and you have to switch all the wires over. I drew a diagram when I did it and will go back and compare to the other 73 convertible sitting next to it. Has to be in that section of wiring since that goes to ignition.

I have not tried putting the fuse back in the #6 plug that Ford says has the radio on it. Without a fuse the radio comes on and buzzes. I do not know if it ever worked car has sat for 26 years now.

No turn signals either at any point. One more day of this and I call it quits on this one and move onto something else. I have no patience left. It can sit there for 35 years like the Mach 1 has just would like to drive it a little.

Who is closest to me that knows this stuff that needs a vacation in the mountains, lol.

I appreciate any suggestions I just have no idea where to start or what to look for.

 

[Carolina_Mountain_Mustangs]

Ok went an pulled the plug apart for the turn signal ignition hookup. That is one big issue. I had put the wires in the correct sequence but was working from the face of the plug instead of the rear of the plug. So everything was in a mirror image position.

So not turn signals work and the #6 fuse does not blow. Still no engine turn over when I turn key but turns over when straight wire. So I will go back and see what i can find. Did make some gain which is good I was getting frustrated for sure.

 

[boilermaster]

Ok David,

think of your cranking circuit like this:

power is supplied to the ignition by a fuseable link located at the battery side of the starter relay.

When the ignition key is turned to the Crank position, power is sent to the park/neutral switch.

if the shifter is in park or neutral (or jumpered) , power is then sent to the S terminal at the starter relay (starter relay has to have a good ground)

There is a coil in the starter relay that when energized pulls a set of contacts together and supplies

power to the starter.

That's how it works.

What you stated in one of your last posts (no power to either of the red wires) at the park/ neutral switch, was the ignition key in the Crank position? if the key was just in the Run position you will not have power to either of the red terminals at the park/neutral switch.

What we want to do here is supply power to the s terminal of the starter relay when the key is in the Crank position.

What you tell us is suggesting that no power is being sent from the ignition switch to the park/neutral switch when the ignition switch is in the Crank position.

SUGGESTING THAT THE IGNITION SWITCH IS BAD OR OT OF ADJUSTMENT

 Not saying that the starter relay terminals S and I cannot be reversed, cause it is possible,

but you still need voltage thru the park/ neutral switch in the CRANK position.

                            Boilermaster