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Posted By Discussion Topic: electrical troubleshooting problem     TomO 04-21-2015 @ 6:23 AM reply profile send p.m. Senior Posts: 7257 Joined: Oct 2009 I am glad that you resolved your problem. Your test results all show that the battery connection is bad. A circuit with no current flowing, can show a voltage with a volt meter. that is why I asked you to measure with the starter button engaged. High humidity conditions can cause corrosion at the battery terminals. You can add the corrosion inhibiting felt washers under the cables or coat the terminal with a light grease like vasolene to inhibit the corrosion. Tom fordmerc 04-20-2015 @ 12:25 PM reply profile send p.m. New Member Posts: 180 Joined: Oct 2009 PROBLEM RESOLVED! I cleaned the NEG batt terminal and all is well! - it didn't look bad even after disconnecting for cleaning. Lesson learned. Thanks for the help and the patience to deal with amateurs. DD931 04-20-2015 @ 11:47 AM reply profile send p.m. Member Posts: 66 Joined: Nov 2014 These are classic symptoms of a bad/corroded battery connection - either directly at the battery or in some close by connection. Do your cables have replacement connectors at the battery? These are notorious for this problem. Look for bad connections at the cable/battery connectors, either in the cable itself or the connection to the battery. Be sure the parts are shiny clean and free of corrosion before assembly!! The ends should be soldered to the cables. fordmerc 04-20-2015 @ 11:17 AM reply profile send p.m. New Member Posts: 180 Joined: Oct 2009 Car started and ran well on Dec 27. Sat untouched until this week. All wiring was new, starter approved by re-builder 1000 miles ago) I believe that all connections are correct. Tests: 1. Meter COM to batt NEG, meter POS to Starter terminal = .01V (which is baseline on the meter) (starter button and solenoid buttons pushed separately) 2. Volt drop check: Batt pos to batt neg=6.50V; batt neg to left side solenoid=6.50 V; head bolt to left side solenoid=6.50 V i.e., no volt drop 3. Solenoid check: push up on button = continuity, but no voltage change. This is with “new” solenoid. Also tried old “original” solenoid with same result Tried: connect batt NEG to starter terminal: nothing happens Ammeter in line between POS batt terminal and ground wire shows no current at rest Note: Sometimes horn relay chatters, sometimes the horn will sound. Sometimes a chatter is heard near the starter when starter button pushed, mostly not. Disconnecting, then reconnecting the battery at POS terminal may have some effect on this (?) So: the problem seems to be that insufficient current goes to starter. I could blame the starter solenoid if it were not for the horn phenomenon which seems to be doing the same thing. For this reason also, I am reluctant to blame the starter. Any further comments will be appreciated. TomO 04-20-2015 @ 7:12 AM reply profile send p.m. Senior Posts: 7257 Joined: Oct 2009 Have you made any wiring changes recently, or was this car running? If you made wiring changes, it would be wise to check that the battery cable is going to the drivers side of the solenoid and that there is a thick yellow wire also going to that side of the solenoid. The starter cable should come from the passenger side of the solenoid to the starter. If you have not made any wiring changes, this would be an opportunity to learn how to do a voltage drop test to determine where the fault is located. A voltage drop test is just using your voltmeter to check resistance in a circuit or to find an open circuit. To check out the starter circuit, connect your volt meter COM lead to the NEG post of the battery and then connect the POS lead of the meter to the starter motor terminal. Read the meter with the starter button pressed. If every thing is OK, the meter should read 0.3 volts. If you get this reading and the starter is not turning, the starter is either hung on the flywheel or defective. Higher readings indicate a problem in the circuit. If the reading is above 5 volts, the solenoid is not delivering the correct voltage to the starter. If the reading is between 0.3 and 1 volt, there is excessive resistance in the circuit. Move the POS meter lead back to the previous connection and repeat the test. Continue this process until you get a reading that allows for 0.1 Volt per connection. Let me know how the test turned out. Tom cliftford 04-19-2015 @ 8:40 PM reply profile send p.m. Senior Posts: 845 Joined: Jan 2014 If you do all the checks mentioned in the last post and get the same results, you almost certainly have a starter motor problem. Pull it and have it repaired or replace it. supereal 04-19-2015 @ 2:07 PM reply profile send p.m. Senior Posts: 6819 Joined: Oct 2009 Check the connection between the ground strap and the firewall. The majority of old car electrical problems are due to faulty grounds. There should also be a ground strap from the firewall connection to one head stud. We also run a ground cable between that point to one of the starter mounting bolts. A 12 volt cable with two eyelet end will work fine. Be sure your battery cables are, in fact, correct. If the cables get very hot when cranking, it is likely they ware undersized. fordmerc 04-19-2015 @ 12:30 PM reply profile send p.m. New Member Posts: 180 Joined: Oct 2009 Starter clicks, horn clicks, no start, no horn. Horn seemed Intermittent. Lights OK? 2 good batteries tried. 7 volts at all points tested. Help me troubleshoot since I never understand electricity . (On a '39 Merc) Thanks

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