Hello! I have a 1973 1.7 with an ignition problem... when I turn the ignition key to start, the engine does not crank. I have a couple of questions, but first the background...

The car has a new ignition switch, a new trunk-to-trans ground strap, new negative battery cable, and new (rebuilt) starter. I cannot start the car with the key (ignition switch)... the only way I can start the car is by turning the key then "jumping" the solenoid at the starter (all that proves is that I have a good ground, a good starter and good + running to the starter).

The car started fine (for about 3 months) after I installed a brand new starter switch then, once in a while, I'd have to turn the key a few times for the starter to kick-over. Eventually, the car would not start at all with the key. The solenoid wire is plugged into the starter and looks to be a good connection.

Question: Is it likely that my new ignition switch went bad in such a short period of time?

Question: There is a "seatbelt idiot light" on the dashboard, but I've never seen it come on (with or without passenger in car or seatbelts on or off). In a 1973 1.7, is the seatbelt idiot light a "passive" system or could I have a seatbelt problem (i.e. under the passenger seat) that is keeping my starter from starting?

Question: On a 1973 1.7, is there anything (like a relay or fuse) between the battery, starter switch and solenoid that I need to look for (i.e. is there a starter relay under the dash)?

Thanks in advance for any troubleshooting help ideas you can provide. I am tired of reaching under the car every time I want to start it! :-)

Chances are the switch is ok. Why was the new switch installed? Don't have a schematic in front of me to know if there's a seat belt interlock but that's never happened on my 74 with the belt on or off.

Look under the passenger seat to see if there is a logic circuit there.
If so, its about 2.5 inches long. It will look like a relay.
If its there, let us know...its a 74 thing, but seems to have shown up in later 73's that I have seen...

If not.
You are looking for the yellow wire that comes out of the ignition switch and goes through the relay board in the engine bay and then goes to the upper most spade terminal on the starter.

Using a volt meter and sewing needles, check it like so.
Use the sewing needles pushed right through the middle of the wire so you contact the wire inside and you dont have to cut the wire to test it.

Starting at the front, just under the dashboard, clipped to the front firewall is the main harness heading towards the engine bay.
You can open that up and find the yellow wire..its a fat one.
Take the needle, push it through the center of the wire.
Make sure the needle never touches ground...
Using the meter set to DC voltage, put the red lead on that pin and the black on a good known ground...the underdash screw work well.

Turn key to start and see if you have power on the yellow lead.
If you are not sure, check the fat red wire the same way to make sure power is getting to the ignition switch to begin with.

I do both wires...then you know that power is coming from the battery to the switch (RED) and power is going back to the starter (Yellow)

If you pass both tests, move to the rear of the tunnel and access the wiring harness just before it goes through the rear firewall and run the same test on the yellow wire again...this would be after any logic circuit and any cut wires in the tunnel...so you want to test there.
Use the pin and meter again.

Now the next test is in the engine bay.
Follow the harness to the relay board.
Find the yellow wire as it goes into the relay board and test it.

From the starter, so the same test on the yellow wire.

By using the pin/meter test you can narrow your search down to find the break in the wire...

Basically its a simple circuit.
Red wire is bolted to the batter terminal.
Red feeds the ignition switch.
Yellow comes out of the ignition switch and goes to the starter solenoid.
Yellow has 2 or 4 connections in line...
Two under the passenger seat (if so equipped) and two at the relay board.
You need to find the dirty one.

Rich

Rich:

Thank you so much for your help. I followed your instructions and found:

1. Power under the dash but nothing on the "big yellow wire" in the same location. I am assuming that my new ignition switch has failed? I wouldn't think that to be likely, but know no other failure point in that area.

2. On my 1973 1.7, there is no ignition relay under the passenger seat. It appears that there are two wires running from each seat belt clasp and seat pressure sensors that (in theory, though it doesn't work) turn a light on on the dashboard if the ignition is on and someone is sitting in a seat without wearing a seat belt.

Again... thank you for teaching me the trick about the sewing needle. I am sure I can use that well into the future!

Keith

I had something like this happen just last week. When I tapped on the top of the voltage regulator, the car turned over like a champ. Even my new out of the box unit does this. Something to add to your attempts to sort out the issue.

GOOD LUCK !!!!

Kfieler,

After you remove the plastic ignition switch from the lock and tumbler assembly, plug the plastic switch back into the female socket under the dash. First look at the back of the female socket and make sure that the female terminal for the big yellow wire has not pushed back and is fully engaged with the male terminal. If all is good then try turning the switch with a small flat bladed screwdriver all the way clockwise and see if it now sends power to the big yellow wire. If not the switch is likely bad. If it does now send power to the big yellow wire your plastic switch is likely good. You might need to replace the lock and tumbler. I recently did this on my car because my lock and tumbler had worn to the point that it did not have enough travel to make contact inside the plastic switch.

Hope this helps.

My '73 1.7 had this problem. The DAPO had just turned the ignition to ON and then used this big button under the dash to engage the starter. I ordered a new ignition switch (electronic portion) and installed it. Still wouldn't kick the starter over. I pulled the ignition switch (mechanical portion with keylock, etc) out and turned the key. It wasn't traveling far enough to kick the electronic portion into the START mode. I just took the dremel out and cleared away more of the path for the mechanical turning portion to allow longer travel... that allowed it to turn the switch part to the START area... Not sure why the tumbler section didn't turn far enough. Either it was a later model? The new electronic switches were a bad batch? I dunno? But that worked for me.

Try plugging in the new switch and turning it with a screwdriver and see if it works. If it does, grind out part of the tumbler doohickey...