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Thanks. Ran out of daylight (and positivity) yesterday, so took a break. I'm talking to Bob this morning. Since I've eliminated the VR, alt, tach, and fuel gauge from previous testing, it seems to me it's got to be the heater or wiper circuit. Will post what I find out and next steps. Evan Quote:
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I was able to drop the dash about 3/4" which actually made a huge difference in being able to fit my hand up behind the fuel gauge so I got the gauge put back together. I was not able to get the two dashboard end screws (behind the doors) started and gave up before I hurt the car or me. Will also check with ERA on tips to get the dash into just the right position to get those screws started. Unfortunately the visor that broke was from Finish Line with the gold engraving. Replacement and a spare are ordered. That was easy enough. Evan |
Here, this test will take less than five minutes, requires no wire cutting and, if successful, will make your car drivable (excluding wipers, gauges, and heater).:cool:
http://38.134.118.239/igswitchtest001.jpg |
Pat,
This looks great! Talking to Bob I checked the ignition light for short to ground, but it's good. He suggested I try to duplicate a symptom I noticed Friday next--with the fan unplugged and car running, the ammeter swung positive when the fan relay was energized. After that I was going to start checking for shorts to ground at the fuse box, then into the loom at this point, but will give your idea a try first. It will likely be tomorrow evening before I get a chance. Evan |
And if that test is successful, then the quick way to find the short would be to invest in a short and open finder tool. You can get fancy ones, or there's a couple on Amazon for less than $30. Like this: https://www.amazon.com/allsun-Automo.../dp/B07BC4X28Y
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Removed the ignition light from the dash for access. Pulled the double green wire off the ground spade of the light socket. Ran a fused jumper between the accessory terminal on the ignition to the grounded lug of the ignition light. Turned key to ON position. No light.:confused: Started engine and light came on while cranking and extinguished when engine started. Ammeter was slightly negative (~1A) with engine running. Turned on headlights and ammeter dropped to ~-12A. Revved engine, but ammeter didn't budge. I'm sure I learned something, just not sure what. Maybe that I can definitely eliminate the gauges as a short path? |
That's progress. For the next set of tests, you will leave the double green wire disconnectied from the light for everything below.
1) Remove the G/R wire from the ignition light but leave your fused jumper wire running to the light. Turn the ignition switch ON but do not start the car. Touch a known good ground lead to the exposed pin of the light and observe that it illuminates. Then, using a VOM, test for either a) 12v+, b) 12v-, or c) neither one at all at the disconnected G/R wire. Report the findings. 2) Plug the G/R wire back on to the ignition light. With the ignition ON, and the car not running, the light should be "ON" but you report that it is not. Try running a known good ground wire to the alternator and voltage regulator and touch different spots on both those components just to see if you can get the ignition light to illuminate. For instance, touching a known good ground wire to the VR case and making the light come on each time you did that would be a really nice sign. Report back. 3) Insert a fuse in to Fuse #3 and turn the key ON, but do not start the car. See if your gauges, heater, and wipers work or if you blow the fuse doing that. Report back. We are making progress.;) |
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Running second test now... |
Can you get that ignition light to illuminate by just running 12v+ to one pin and 12v- to the other pin? All we're doing here is just testing the light bulb to see if it will come on.
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I used the DVM rather than trying to see the ignition light since I'm working alone.
Ignition light side terminal grounded to block, G/R wire connected to ignition light center terminal. DVM clipped to ignition light center terminal. With ignition "on" (no 3 fuse): Light to VR ground 0V Light to alternator case 0V Light to alternator Batt terminal 13.7V Light to all other alt terminals 0V Turned key off, inserted fuse, turned key on. Alt spiked to -15A and fuse blew. Light did not illuminate. |
The resistance across the ignition light terminals is 7.5 Ohms. It lights when battery power is applied.
Need to head to work, but will check back later today. |
OK, fuse out, run a 12v+ line to the pin on the light that originally had the two green wires that you removed, and the G/R wire is now attached back to its pin. When you do that does the light illuminate? If not, and you're absolutely 100% positive that the light works and that you are giving it 12v+ on one side, then that means it is not getting a return path on the other side through the VR. Double check this test as it is important.
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All we're doing on this test is just making sure the ignition light is not broken somehow and that the G/R wire coming from the voltage regulator does indeed provide a path to ground when the car's alternator is not charging. When behaving normally that G/R wire will provide a path to ground until the car begins charging, and then the path is gone. That's what makes the ignition light come on and off.
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ammeter
Hi,
Hard to find shorts. While you are in there it might be a good idea to get rid of the ammeter and run a voltmeter. All the power for everything goes through the ammeter and when not functioning can heat up quickly and start a fire. I don't think it's worth the risk. Just my perspective, 33 years in electronic industry. Perry :cool: |
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Thanks. I will run this test when I get home tonight and post the results. Evan PS I have a short tester ordered. It should be here Friday, so hopefully can isolate the wire by then. |
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I'm back to suspecting the voltage regulator, although maybe I should disconnect the fan and wipers to eliminate them as the source of the short (assuming I can get to the connections)? Quote:
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Some additional data. Not sure what to make of it other than there is definitely a connection to ground on the fuse 3 circuit, and it's not between the ignition switch and the fuse (that tests as open). All tests were made with the battery cut off in the "off" position. The ignition light is out of the circuit.
Testing the right side of the fuse terminals to ground: 1 Open 2 Open 3 0.7 Ohm 4 Open 5 Open 6 1 Ohm 7 0.7 Ohm 8 0.8 Ohm |
Try a different battery, I had a internal short once and it gave me hell. Sounds like it may be your problem. Also it is easy to do .
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Remove Fuse #3 and keep it out throughout the testing. Likewise, remove the double GREEN wire from the pin on the ignition light and keep it off throughout the testing. Run a fused wire from the ACC terminal of your ignition switch (WHITE wire) to the exposed pin on the ignition light that had the two green wires on it. The G/R wire should still be attached to the ignition light normally. Then remove the four wire plug from the voltage regulator and jumper a new ground wire from ground to the G/R wire hole in the plug. Do not re-insert the plug, just leave the temporary ground jumper in it. Turn the key "ON" and see if the ignition light comes on. If the light comes on, check to see if you have 12v+ at the Y/R wire hole on the plug. Report back. |
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