Tgriffin91 27 Report post Posted March 10, 2015 Back again. I have two plugs that look the same to me and do not know what they go to. Maybe you guys can help. Engine is a 302. Pretty much stock with the exception of powersteering added.C4 auto trans. One is definitely green, and I have that hooked up to the transmission. I'm pretty sure it goes to the neutral safety switch. The other wire also appears very faded green, but I am suspecting it may have been blue originally. In my electrical manual both tell me to see other document which I do not have... Any idea what these wires go to? Quote Share this post Link to post Share on other sites
machm1970 180 Report post Posted March 10, 2015 I may be wrong but here goes: The neutral safety switch has several wires (I'm not home to look at mine so I'm going from memory). If memory serves me correctly it's a 4 or 6 pin connector. I think what you are thinking is the neutral safety switch is actually the light for the inside of the shifter, it should be light blue with a red stripe. I think I remember reading that the grren wire isn't used, it was a prototype thing that made it to production but isn't hooked to anything. Matt Quote Share this post Link to post Share on other sites
Tgriffin91 27 Report post Posted March 10, 2015 Machm1970, Thank you for your reply. That would make life easier. The wire does appear to have a bit of red left close to the plug. I will see if the light is on, and if not, switch it and see if it comes on. Can anyone confirm this? Quote Share this post Link to post Share on other sites
Guillaume69 150 Report post Posted March 10, 2015 Yup, your PRNDL light. Quote Share this post Link to post Share on other sites
Midlife 814 Report post Posted March 11, 2015 That green wire with the black plug looks very similar to the AC clutch/compressor signal line. What's unusual is the black trace on the wire near the firewall side. The other plug is your PRNDL signal. The NSS/Backup light switch plugs into a four prong square plug: two black/red wires and two red/blue wires. 1 JayEstes reacted to this Quote Share this post Link to post Share on other sites
Tgriffin91 27 Report post Posted March 11, 2015 Thank you Midlife. The light was off with it in the green and came on when I plugged it in to the other. So thank you all. I do not have an AC car so green is just unused then. :) Thank you all. After wiring I'm still having issues. Think it has to do with fuel delivery though, not wiring. Quote Share this post Link to post Share on other sites
Brian Conway 264 Report post Posted March 11, 2015 Same wires just a different angle. Brian Quote Share this post Link to post Share on other sites
Midlife 814 Report post Posted March 12, 2015 Well now...one of those large female bullets has a wire splice down its wire. And looking at the second picture, it appears that wire doesn't come out of the wire bundle in the center of the grommet but from the bottom! So what's really going on here? I dunno. At first, I thought this might be a 70, where there's a second large female (third if AC) for the carb solenoid, but that molding is white and the wire is a greyish blue. If this is a 69, then I think someone added an extra line, perhaps for a resistor wire bypass? One needs to examine the passenger side of the firewall to see what's truly going on here. Quote Share this post Link to post Share on other sites
Brian Conway 264 Report post Posted March 12, 2015 Well golly let me explain. The splice is for the electric choke. The blue wire is for the added oil pressure gauge and yes a 69. The two taped together are the subject of the post and it is not my intention to mislead just thoughtless I guess.Brian Quote Share this post Link to post Share on other sites
Midlife 814 Report post Posted March 12, 2015 Oh...that's tape on the two large female bullets, not a splice/junction. My bad. Quote Share this post Link to post Share on other sites
Tgriffin91 27 Report post Posted April 2, 2015 Alright all. I cleaned out the carb as I thought that was the problem however it was not as dirty as I had perviously thought. Got everything reinstalled new gaskets and everything and am still having a starting issue. I believe the issue is with the resistor wire to the ignition coil. I have a buddy coming over later this week to help test more but with the key in the On position I get 0V to the coil when placing negative to battery - and positive to + on coil. This typically means the resistor wire has gone bad correct? I tested it with the connection both attached to the coil and pulling it off and testing it that way. When I crank the engine it will try to go but wont stay running. I wanted to try cranking it to see if it gets voltage but don't have enough hands. Any other ideas or tests I can do on my own? Quote Share this post Link to post Share on other sites
Tgriffin91 27 Report post Posted April 2, 2015 P.S. Thanks for the pictures Brian! Quote Share this post Link to post Share on other sites
Midlife 814 Report post Posted April 2, 2015 Alright all. I cleaned out the carb as I thought that was the problem however it was not as dirty as I had perviously thought. Got everything reinstalled new gaskets and everything and am still having a starting issue. I believe the issue is with the resistor wire to the ignition coil. I have a buddy coming over later this week to help test more but with the key in the On position I get 0V to the coil when placing negative to battery - and positive to + on coil. This typically means the resistor wire has gone bad correct? I tested it with the connection both attached to the coil and pulling it off and testing it that way. When I crank the engine it will try to go but wont stay running. I wanted to try cranking it to see if it gets voltage but don't have enough hands. Any other ideas or tests I can do on my own? Remove the + side to the coil, and with the key in RUN position, measure the voltage from the wire that was connected to the + side of the coil to battery ground. With no load, you should see 12+ volts. You can also measure the voltage at the + side of the coil with the engine running and this wire connected, and it should be somewhere between 10.5 and 11.5 V, typically. Quote Share this post Link to post Share on other sites
Tgriffin91 27 Report post Posted April 2, 2015 Sorry by the On position I meant accessory. Is that also the Run position, just for clarity? I measured from the cable to the negative battery terminal and got 0V. That should still give me the same thing as to battery ground right? Checked battery and it was at 12.26V. Quote Share this post Link to post Share on other sites
Midlife 814 Report post Posted April 2, 2015 ACCessory position is different than the RUN position for the coil wire, yes indeed. Test it in the RUN position. Quote Share this post Link to post Share on other sites
Tgriffin91 27 Report post Posted April 2, 2015 If I understand correctly though in the RUN position the circuit bypasses the resistor wire and provides direct voltage to the coil. The car will fire if I am cranking it but as soon as I release the key it dies. That is why I was thinking it was the resistor wire. I will test voltage in the RUN position today and post back. Quote Share this post Link to post Share on other sites
Midlife 814 Report post Posted April 3, 2015 If I understand correctly though in the RUN position the circuit bypasses the resistor wire and provides direct voltage to the coil. The car will fire if I am cranking it but as soon as I release the key it dies. That is why I was thinking it was the resistor wire. I will test voltage in the RUN position today and post back. No. It is in the CRANK position that the circuit bypasses the resistor wire. From your symptoms (cranking = fire, but release the key from CRANK to RUN), there's a problem with your wiring. Do you have a Ford tach? If so, try bypassing it and try to start the car again. If not, there's something definitely wrong if you're not getting voltage out to the coil with the key in the RUN position. Quote Share this post Link to post Share on other sites
Tgriffin91 27 Report post Posted April 5, 2015 Yes something is wrong. In the Run position I get no voltage to the coil. What could be the problem? Quote Share this post Link to post Share on other sites
Midlife 814 Report post Posted April 6, 2015 I've seen some bad engine gauge feed harnesses. Unplug the three prong plug that goes to the oil, temp, and coil, and with the key in the RUN position, test for voltage on the end female plug (that's for the coil). It should read 12V with no load on it. If it reads 0 volts, then there's a problem with the underdash harness; if not, the wiring issue is outbound of that plug. Quote Share this post Link to post Share on other sites
Tgriffin91 27 Report post Posted April 6, 2015 Will do. Thank you for your help. I doubt it is the underdash since that got sent out to you. Probably something in the engine harness. I'll try and test tonight when I get home and let you know. Quote Share this post Link to post Share on other sites
Tgriffin91 27 Report post Posted April 8, 2015 I tested from the end female plug and got 0V so looks like there is something wrong in the underdash. What is next to check? Fuses? Power to the ignition switch? I appreciate all the help! Quote Share this post Link to post Share on other sites
Midlife 814 Report post Posted April 8, 2015 OK...let's stop and think about this for a minute. Is this a tach dash car? Is the tach connector plugged into the tach? If so, remove it and jumper the two leads on the underdash harness. I checked my records and your harness is not a tach configured dash...OK. If not a tach dash car, what else can cause no voltage at the coil output pin? Did you do the test with the key in RUN position? Do the other pins have voltage of any sort? You can sometimes get a bad reading if the other lead is not properly grounded. The pink resistor wire runs from the ignition to the firewall plug, so either that pink resistor wire is broken or not connected at the ignition switch. The pin could come out of the ignition switch plug and not make contact. Another test: unplug the brown wire at the starter solenoid and put the key to RUN. Measure voltage at the brown wire...you should see anywhere from 9 to 12V. It's got to be something simple...with over 500 harnesses I have examined, only 3 have blown resistor wires. Worst case scenario: pull the underdash harness and send it back to me on my nickel and let me re-examine it. I stand behind my 2 year no questions asked warranty. Quote Share this post Link to post Share on other sites
det0326 179 Report post Posted April 8, 2015 OK...let's stop and think about this for a minute. Is this a tach dash car? Is the tach connector plugged into the tach? If so, remove it and jumper the two leads on the underdash harness. I checked my records and your harness is not a tach configured dash...OK. If not a tach dash car, what else can cause no voltage at the coil output pin? Did you do the test with the key in RUN position? Do the other pins have voltage of any sort? You can sometimes get a bad reading if the other lead is not properly grounded. The pink resistor wire runs from the ignition to the firewall plug, so either that pink resistor wire is broken or not connected at the ignition switch. The pin could come out of the ignition switch plug and not make contact. Another test: unplug the brown wire at the starter solenoid and put the key to RUN. Measure voltage at the brown wire...you should see anywhere from 9 to 12V. It's got to be something simple...with over 500 harnesses I have examined, only 3 have blown resistor wires. Worst case scenario: pull the underdash harness and send it back to me on my nickel and let me re-examine it. I stand behind my 2 year no questions asked warranty. Couldn't it be possible that the ignition switch may have a bad contact also. Dave Quote Share this post Link to post Share on other sites
Tgriffin91 27 Report post Posted May 5, 2015 All, Thank you for your comments and suggestions. I took a break due to frustration as well as busy work and home Life. I got back to the mustang today and still no Voltage in the run position. I took the lead in the distributor off cleaned it and put it back on. Still nothing. I tried cleaning the pins in the ignition switch and nothing. I tried unplugging it and plugging it in also. No luck. It looks like I am running out of options. Can anyone give me More things to test? Should I check continuity through the dash harness? Quote Share this post Link to post Share on other sites
LoneWolf2U 136 Report post Posted May 5, 2015 I start by verifying the wires first. Disconnect the ign switch, the coil + lead and the brown wire at the sol. Check the wire from sol brown to coil + for continuity. No, check and repair, Yes move to coil + to firewall plug in and check. Still have continuity? No, check and repair wire/connector. Yes replug firewall harness and check for continuity from coil + to ing switch plug. No, check connectors and wire. Yes check ign switch for proper function. Quote Share this post Link to post Share on other sites
