ammeter harness continuity
Thread Starter
Intermediate
Joined: Oct 2006
Posts: 34
Likes: 1
From: Leesburg, Florida
ammeter harness continuity
I picked up a '64 327/300 a short while back and am intending to do the electrical upgrades - fusible links and inline fuses - I've been reading about here. Been going through the wiring diagram and the car's wiring trying to understand everything.
My question is this - concerning the ammeter harness connector. I disconnected the terminal connector at the horn relay which had the red wire to the Bat terminal of the Ign sw and the blk/wht wire to the ammeter spliced together sharing the connector. Also disconnected the blk wire at the starter solenoid that goes to the ammeter. I tested the ammeter harness connector and found continuity between the 2 pins in the ammeter connector itself and continuity between all 4 entities (each pin has continuity with each wire). I don't understand this as one pin is for the blk wire and one is for the blk/wht wire. Can you please explain.
With the Ign sw in "run" (engine not running) both pins have 12.36 volts. With engine running both have 13.xx volts (it varies) and I can't really tell if there is any difference between the two because the voltage is not constant.
My question is this - concerning the ammeter harness connector. I disconnected the terminal connector at the horn relay which had the red wire to the Bat terminal of the Ign sw and the blk/wht wire to the ammeter spliced together sharing the connector. Also disconnected the blk wire at the starter solenoid that goes to the ammeter. I tested the ammeter harness connector and found continuity between the 2 pins in the ammeter connector itself and continuity between all 4 entities (each pin has continuity with each wire). I don't understand this as one pin is for the blk wire and one is for the blk/wht wire. Can you please explain.
With the Ign sw in "run" (engine not running) both pins have 12.36 volts. With engine running both have 13.xx volts (it varies) and I can't really tell if there is any difference between the two because the voltage is not constant.
Safety Car
Joined: Mar 2009
Posts: 4,191
Likes: 951
From: Corpus Christi, TX
Each pin on the ammeter connector should have continuity to only one wire with the wires disconnected from the horn relay and starter solenoid. The problem is the wire connected to the horn relay connects to just about everything else in the car that gets power from the 12 ga red wire on the firewall connector just above the ammeter wire. That's why your continuity check seems strange.
If you really want to check the ammeter wiring, you will have to disconnect the black/white wire at the horn relay as well as at the starter solenoid and check continuity between each ammeter terminal and the end of the corresponding wire.
If the ammeter circuit is working correctly you will get about the same voltage reading to ground at each ammeter terminal, whether the engine is running or not. If the ammeter circuit is working correctly, though, you should get a small (< 1/2 volt) to zero voltage reading across the two ammeter terminals. The polarity and amount of the voltage will depend on whether the car is charging or discharging the battery when you measure the voltage.
If you really want to check the ammeter wiring, you will have to disconnect the black/white wire at the horn relay as well as at the starter solenoid and check continuity between each ammeter terminal and the end of the corresponding wire.
If the ammeter circuit is working correctly you will get about the same voltage reading to ground at each ammeter terminal, whether the engine is running or not. If the ammeter circuit is working correctly, though, you should get a small (< 1/2 volt) to zero voltage reading across the two ammeter terminals. The polarity and amount of the voltage will depend on whether the car is charging or discharging the battery when you measure the voltage.
Last edited by Avispa; Apr 4, 2011 at 08:43 PM.
Thread Starter
Intermediate
Joined: Oct 2006
Posts: 34
Likes: 1
From: Leesburg, Florida
Yes, I did disconnect the blk/wht from the horn relay (and consequently the red wire since it is spliced to the blk/wht sharing the same terminal connector - one of those 'u' shaped type). I also disconnected the blk at the solenoid. But, I got continuity, between both ammeter connector pins and each pin had continuity with both wires.
But, maybe I made a mistake somewhere - I'll do it again tomorrow.
Thanks Avispa.
But, maybe I made a mistake somewhere - I'll do it again tomorrow.
Thanks Avispa.
Le Mans Master
Joined: Nov 2000
Posts: 7,246
Likes: 21
From: Going too fast over the hill. Iowa
If you pull the Battery meter connector (it's not an ammeter) and use a volt meter on the connector terminals, you should see about 12.5volts with the engine off on each harness contact.
If you do, you have continuity and a good battery.
The Battery meter displays the voltage difference between the horn relay (charging connection) and the starter solenoid (battery connection). With the engine off (no alternator charging) the voltage should be the same.
If you do, you have continuity and a good battery.
The Battery meter displays the voltage difference between the horn relay (charging connection) and the starter solenoid (battery connection). With the engine off (no alternator charging) the voltage should be the same.
Thread Starter
Intermediate
Joined: Oct 2006
Posts: 34
Likes: 1
From: Leesburg, Florida
One more.
Clock - I've read here that the clock needs an inline fuse. The '64 wiring diagram I have shows a blk/or wire from the clock going to the top fuse in the fuse panel. So, can you please explain why an inline fuse on the clock?
MagicV8 - stumbled onto your website today - impressive. I'll be re-reading, maybe with a question or two, if you don't mind.
Clock - I've read here that the clock needs an inline fuse. The '64 wiring diagram I have shows a blk/or wire from the clock going to the top fuse in the fuse panel. So, can you please explain why an inline fuse on the clock?
MagicV8 - stumbled onto your website today - impressive. I'll be re-reading, maybe with a question or two, if you don't mind.
Le Mans Master
Joined: Nov 2000
Posts: 7,246
Likes: 21
From: Going too fast over the hill. Iowa
MagicV8 - stumbled onto your website today - impressive. I'll be re-reading, maybe with a question or two, if you don't mind.
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