72 ignition issues

[kbee00]

I have read everything I could find on this topic. I rebuilt the switch per online articles. It worked fine for a couple days. Then intermittent problems for a day. Now it wont start. All auxiliary power works. I measure from ground to Red in crank position - less than .05 volts. I measure across Red and Brown in Run position. 12.06v

Battery is good

Yes I have the spade connectors. I polished both male and female and added dielectric grease.

Has anyone gone the route of relays?

Anyone know where I can find a new switch?

Thank you for your help.

LT

[spider2081]

Lots of folks have installed a relay in the "start" circuit.
Look under the post "Battery or Alternator" in this section. The last diagram posted by azruss is the correct diagram to follow.

[azruss]

AR has new switches

[kbee00]

I found azruss' relay diagram. Thank you.

I want to bypass the output #50 on my switch and use a remote momentary switch instead. I am not seeing any voltage at #50 to ground in crank position. Not sure how to wire the relay in this scenario.

thanks,

LT

[azruss]

power to the 50 terminal comes from the 30 terminal. If all else is working, your fix to the ignition switch at the 50 terminal didn't last. you can still use my relay diagram. connect your remote starter button to the 50 wire between the switch and the relay and pull power from the 30 wire. The wire from the 50 terminal will be disconnected. It would be nice to do this without a disturbing the harness so you can put in a new ignition switch when you have the chance. In that case, you can pull power from any non-switched power source. I would recommend a fuse in the circuit or pull it off the fuse panel. hope this makes sense.

[spider2081]

When in the "start" position did you also measure terminal 30 to ground to be sure the ignition switch was getting fed voltage when in the "start" position?? If yes then-
Did you check for voltage with the wire on terminal 50 and then off terminal 50?? The starter solenoid draws a very high surge current to engage. A poor internal switch connection in the "start" position could drop almost all the voltage. If you have 12 volts on terminal 50 with the wire off 50 and always have voltage on terminal 30 then the ignition switch has a problem. Installing the relay mentioned above would probably correct the issue.

There is a safety issue with installing a separate push switch to start your car. If it is connected to the "hot" all the time circuit in the car, any time the button is pushed the engine will turn over even if its by accident. If the car is in gear it will move and someone could get hurt. If you connect the switch to the "hot in Start and run" circuit to avoid this you are still puttin the starter solenoid current through the ignition switch but another set of contacts.

[kbee00]

power to the 50 terminal comes from the 30 terminal. If all else is working, your fix to the ignition switch at the 50 terminal didn't last. you can still use my relay diagram. connect your remote starter button to the 50 wire between the switch and the relay and pull power from the 30 wire. The wire from the 50 terminal will be disconnected. It would be nice to do this without a disturbing the harness so you can put in a new ignition switch when you have the chance. In that case, you can pull power from any non-switched power source. I would recommend a fuse in the circuit or pull it off the fuse panel. hope this makes sense.

azruss - something doesn't seem right with this suggestion. If I put the PB switch in the Red wire line I will have full amperage going thru a momentary - low amperage - switch.

It would seem better to remove the wire from spade #50 (Red) and connect it to spade on relay #86. Then take Brown wire from one of the #30 (I have two #30 on my ign switch) and connect to relay #87. I pull another smaller brown wire off of #30 to my PB switch to power the coil on the relay (relay #30) Relay #85 goes to ground.

In this scenario, I can put the ign switch in Run position, then use the PB switch to energize the relay coil thus connecting Red to Brown - powering the solenoid on the starter.

My only concern is that i read somewhere that a pink wire is used to pull down the coil on the solenoid. So do i need another relay or do I need to connect it somehow to the PB switch relay? Or do i not need to worry about this? Again, my car is a '72. I have an official wiring diagram and it does not match the wire coloers on my ign switch. For instance, there is a Black tied to a larger blue w/red strip connected to INT on the ign switch. And a pink on #15 of the ign switch and a pink wire and white wire coming out of the ign switch going to a connector. That pink is fused inline. Lastly, there is another black going to - I believe - #30/1

Please advise if I am going down the proper path.

thank you all for your help. I do apprecaite it! my car is stranded in a parking lot - need to get her home!

LT

[kbee00]

Follow up on the push button switch - ign switch bypass relay wiring.

i built the relay wire harness as I listed above. Started on the first push of the button. The gentleman that commented on the safety issue: i agree. i am going to put a STSP (on/off) switch in series with the push button. yes it means an extra switch to engage/disengage but it works for me. fortunate that my ign switch has 2 - #30 spades - makes the wiring harness easier to convert back to stock. did not cut any stock wires.

it took about an hour to make the relay harness and about 10 minutes to plug it into the car - including disconnecting the battery first. Then its just a matter of mounting the relay and PB switch.

Good luck

LT