Ignition switch troubleshooting

[AD6SVO]

I recently purchased a 1986 SVO which I love so much. However, I went to start it up the other day and found that as soon as I let go of the key it turns back and dies. I discovered if I held the key in place it would still run, I have heard horror stories of faulty ignition switches causing fires and the like, so I disconnected the battery and decided to replace the ignition switch asap. So I replaced the switch with a new one from autozone hoping that would fix the problem. I followed all the instructions found in my chilton's shop manual perfectly but to no avail. The key goes in and clicks into the different positions as it should but the car still will not start. Yes the battery is connected again, I can get the door locks to work and the headlights to turn on, but no dash lights, radio, ignition, etc. I'm very positive that it was a faulty ignition switch, and not the actual key lock cylinder, because the old switch was literally falling apart. Please if anyone can give me any troubleshooting advice, related wiring diagrams, or anything I need to check, I would be very grateful.
Whether it matters or not, I did check all the fuses with a fuse tester just in case, and found them all to be working.
Thanks.

[svobrad]

Ignition switch

I would go the Ford dealer and buy the original switch. May cost more but we here have found out that original Ford tune up and electrical parts are superior than off-shore copies.

As you remove the switch you just installed check the way you put it on and make sure connections were done correct. I use dielectic grease on the pins.

Don't understand why you are getting partial power - that sounds like what bad switches do on their way out. Make sure the key switch is engaging the switch also. May be a good time to replace that also. I could not remove mine so had a mobile key shop install the new key switch (with new keys also).

[GAboySVO]

Sounds like the pin from the cylinder that moves the switch is not in the correct place and you are only getting power to the ACC portion of the wiring. Pull the switch back off, put the cylinder in the off position and make sure the switch pin receiver is in the correct position then reinstall.

[AD6SVO]

Great news everybody, I was able to get the problem with the ignition corrected and my svo is now up, and running just fine! Thanks to svobrad and GAboySVO for all of your advice. I made a trip to the ford dealership and purchased a genuine motorcraft ignition switch and ignition key lock cylinder; they are now currently installed in my svo. Unfortunately these two items weren't the cause of the problem though. I traced the lack of power - to the ignition fusible link near the voltage regulator under the hood. So with a new fusible link (gauge #16) installed, my svo is back to normal. Thanks for everything and for making my first experience in the svoca forum a positive one.

[GAboySVO]

Good news. Next time you need to replace the ingintion switch remember to disconnect the battery first.

[SVOJames]

For various reasons, my 86 2A (which has been down for 5 years), had the ignition switch replaced with the battery cables in place.

2 of the 16 gauge links look to have some expansion in the plastic stuff that contains the printed info, I've also got a 20 gauge link that looks bad.

From my non-automotive experience, fusible links look like thicker wire than is normal for the gauge, not something like the "connector(s)" I see on my SVO that is(are) labeled as a fusible link with a GA size. Am I dealing with a 4 or 5 inch wire, or just the part that is contained in the "connector"?

Which fusible link got fried when the switch was connected with battery connected?

James

[AD6SVO]

When I was replacing my ignition switch I did indeed have the battery disconnected. I believe the fusible link got fried when I made the mistake of manually holding the ignition key lock in place to keep the car running. I could detect that electrical melting smell during and immediately after doing this, I'm thinking that this is what burned out the fusible link. (Whether or not the smell was the old faulty switch or the link I don't know for sure) So needless to say I'm almost positive that the fusible link was gone before I ever put the new ignition switch in.

The fusible link I had to replace was 16 gauge, and was indicated by a cube like piece of rubber with a yellow wire going in one end and a dark wire coming out the other. I used a multi-meter set on the ohms reading to test the continuity of the wire (fusible link). When I found a spot in the wire that was complete I cut out the old melted piece and connected a new fusible link to the two complete spots. Luckily the melted part of the fusible link did not go into the area of wire wrapped together in the wiring harness. The new fusible link cost just over $3.00 at autozone (apparently ford dealerships do not sell motorcraft fusible links) and was about 9 inches long, which was more than enough length.

Sorry I don't have a camera to take a picture of the exact fusible link I replaced, but if I remember correctly there are only two 16 gauge fusible links near the voltage regulator. The only thing I can think of is to test the fusible link to be sure which one is bad. And I did have to replace quite a bit of length of wire not just the cube like connector piece.
Hopefully this answers your question, and may be of some help. Good Luck.

By the way - the yellow wire was complete all the way through, only the darker wire had a couple of melted spots.