old-tank Posted April 8, 2015 Share Posted April 8, 2015 After some recent repairs on one of my 55's, I now have an electrical drain. I noticed that after sitting for a few days, it takes longer than expected to charge the battery. I found a drain of 50 mA, which is about what some modern cars have to retain memory in some accessories. None of my other (old) cars have any drain. The work that was done was to R&R the speedometer for repair and R&R the other gauge cluster to repair the temperature gauge. The only thing electrical that was touched was to remove the wires from the amp meter which is working fine.For your viewing pleasure is a wiring diagram attached. Note the black wire from the battery going to the amp gauge and then a red wire that branches to the ignition switch and non switched units. I have removed all wires at their termination with no change --- all wires except the ignition switch and the amp meter --- in the drain. I can't see where there would be a problem with the amp meter since it is just a straight through circuit that works or not....and the ignition switch was not touched and what could go wrong there, it either works or not (I tried both OFF and LOCK positions). Some suggestions would be appreciated before I abuse my creaky old body to remove the ignition switch and remove the top of the dash again to get at the amp meter terminals. I hate electrical gremlins...that's why I don't play with modern stuff.Willie Link to comment Share on other sites More sharing options...
JohnD1956 Posted April 8, 2015 Share Posted April 8, 2015 I would suggest that an original power lead to the radio could be deteriorated and causing a drain. On my 56 the power leads on this unit are the older rubber/cloth insulated wire. But I presume you already changed that. Nonetheless, it may be convenient to disconnect the radio fuse to see if it is the culprit. Link to comment Share on other sites More sharing options...
Larry W Posted April 9, 2015 Share Posted April 9, 2015 FWIW, I once had neighbor who had a '61 or'62 Cadilac with the same problem you're having. What he found was that the mercury switch for the trunk light somehow got bent to a position that never allowed the light to turn off, thus causing constant drain on the battery. Does the light in the refrigerator really turn off when you close the door? Link to comment Share on other sites More sharing options...
Bhigdog Posted April 9, 2015 Share Posted April 9, 2015 Pull one fuse at time and use your ma meter to possibly find the suspect circuit..............Bob Link to comment Share on other sites More sharing options...
avgwarhawk Posted April 9, 2015 Share Posted April 9, 2015 Pull one fuse at time and use your ma meter to possibly find the suspect circuit..............BobGood plan of attack.Also suggested, the trunk courtesy light if equipped. Glove box light if equipped. I have seen these not turning off and draining batteries. Link to comment Share on other sites More sharing options...
old-tank Posted April 9, 2015 Author Share Posted April 9, 2015 Maybe my thinking is flawed or too simplistic. What I see in the diagram that is pertinent is red wires: Red from the charge indicator which branches to the ignition switch (not yet checked), headlite switch that was disconnected (feeds radio, lites...), fuse panel (feeds dome lite fuse [dome lite and trunk lite] and clock fuse that were pulled),voltage regulator that was disconnected, horn relay that was disconnected; everything else is live after ignition switch is ON. That leaves connections at the amp meter (charge indicator) and ignition switch --- any experience with problems at those locations?Willie Link to comment Share on other sites More sharing options...
Joseph P. Indusi Posted April 9, 2015 Share Posted April 9, 2015 The more I read about this the more I run out of possible suggestions, however, in the interest of trying to help I will suggest 2 things. With the battery connected for a few minutes feel the solenoid on the starter and the ignition switch to see if they feel warmer than normal. It seems you have disconnected everything that could be a potential point of trouble due to faulty internals or wiring with worn insulation.Good luck and do post again when you solve this one.Joe, BCA 33493 Link to comment Share on other sites More sharing options...
JohnD1956 Posted April 9, 2015 Share Posted April 9, 2015 Maybe my thinking is flawed or too simplistic. What I see in the diagram that is pertinent is red wires: Red from the charge indicator which branches to the ignition switch (not yet checked), headlite switch that was disconnected (feeds radio, lites...), fuse panel (feeds dome lite fuse [dome lite and trunk lite] and clock fuse that were pulled),voltage regulator that was disconnected, horn relay that was disconnected; everything else is live after ignition switch is ON. That leaves connections at the amp meter (charge indicator) and ignition switch --- any experience with problems at those locations?WillieIt also seems to leave the starter solenoid, the junction block ( which feeds the resistor for the distributor) , the starter relay and the starter switch, which, by virtue of that is the neutral safety switch and then the gas gauge. Of course that would be a lot of failures which seems highly unlikely. I forgot, is there a resistor on the underside of the junction block? Link to comment Share on other sites More sharing options...
old-tank Posted April 9, 2015 Author Share Posted April 9, 2015 Pulled the 10g black wire from the junction block....still no joy. Link to comment Share on other sites More sharing options...
Joseph P. Indusi Posted April 9, 2015 Share Posted April 9, 2015 With the 10 gauge black wire disconnected from the junction block that leaves the starter solenoid still getting +12 volts from the battery. That's all I see left based on the wiring diagram.Joe Link to comment Share on other sites More sharing options...
TexasJohn55 Posted April 9, 2015 Share Posted April 9, 2015 Looks like you are chasing rabbits. Disconnect pos battery cable from the junction block on the fender and recheck. Link to comment Share on other sites More sharing options...
JohnD1956 Posted April 10, 2015 Share Posted April 10, 2015 And if you remove the yellow wire to the junction block at the same time? Link to comment Share on other sites More sharing options...
buick5563 Posted April 10, 2015 Share Posted April 10, 2015 Willie called me to see if I knew what to check. You guys are way better at diagnosing over the interwebz than I am, and this is my era.I would need to lay my hands on it. Link to comment Share on other sites More sharing options...
Bhigdog Posted April 10, 2015 Share Posted April 10, 2015 Twer it me, after checking the obvious stuff I'd start at one end and remove one item at a time until I saw the MA meter null out. Problem is it could be a double corrosion leak type failure in that an item that should be isolated when the Ign Sw is off isn't and that unit also has a leak to Grnd. ..............Bob Link to comment Share on other sites More sharing options...
55 SURVIVOR Posted April 10, 2015 Share Posted April 10, 2015 Willie:battery ok,internal plate shorted?just A thought Mark Link to comment Share on other sites More sharing options...
old-tank Posted April 10, 2015 Author Share Posted April 10, 2015 I'll probably just disconnect the battery when I'm not using the car for now...until I find a good reason to pull the dash .In the meantime before I take off to play in the streets, my diagnostic approach: noted battery drain, found small spark at negative battery terminal when connecting, found 12.5V between neg terminal and neg cable (at 50 mA), removed black wire from junction block (there are 2 separate terminals on the junction block), no drain now, so that eliminates the starter, solenoid, etc., attached ohm meter between black wire and ground and found continuity that remains after removing red wires as noted earlier. Checked another 55 and found no voltage mA or continuity at those locations. Link to comment Share on other sites More sharing options...
Joseph P. Indusi Posted April 11, 2015 Share Posted April 11, 2015 IF you removed all of the red wires connected after the ammeter, then that leaves the ammeter itself or the wiring having a weak connnection to ground. These are not that complicated compared to the current cars. Very frustrating!Joe Link to comment Share on other sites More sharing options...
old-tank Posted April 13, 2015 Author Share Posted April 13, 2015 IF you removed all of the red wires connected after the ammeter, then that leaves the ammeter itself or the wiring having a weak connnection to ground. These are not that complicated compared to the current cars. Very frustrating!JoeCorrect on all counts. I'll probably check the ammeter next (maybe next year since it is already in the 90's in my shop and that is outside my comfort zone). No big deal to just disconnect the battery when no in use, just aggravating .Thanks to everyone who offered suggestions and support.Willie Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now