Charging voltage too high.

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I need some help! I did the relay thing. It helped some on the over charging but now the car won't shut off until I pull the inline fuse or remove the ground in the relay.... was a switch required inline on the ground?
 
Chris Beauchamp said:
I need some help! I did the relay thing. It helped some on the over charging but now the car won't shut off until I pull the inline fuse or remove the ground in the relay.... was a switch required inline on the ground?
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Usually "the relay thing" means adding a 30 A relay to supply IGN power when the key is in RUN position. Check that when the key is in OFF that you don't measure 12 V at coil+ of the relay. If you do, find where it is coming from. You should have wired so the key's IGN output runs only to coil+ of the relay and nowhere else. Everything else that blue wire formerly fed should now come from the relay's output terminal (usually 87, with 30 is the 12 V supply). My guess is you have the output looped back to coil+ thru consumers of IGN, which forms a self-latching relay.
 
BillGrissom said:
Usually "the relay thing" means adding a 30 A relay to supply IGN power when the key is in RUN position. Check that when the key is in OFF that you don't measure 12 V at coil+ of the relay. If you do, find where it is coming from. You should have wired so the key's IGN output runs only to coil+ of the relay and nowhere else. Everything else that blue wire formerly fed should now come from the relay's output terminal (usually 87, with 30 is the 12 V supply). My guess is you have the output looped back to coil+ thru consumers of IGN, which forms a self-latching relay.
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What's odd is I do have 12 volts at the coil when I turn the key back to off... it only goes away when I pull the fuse or ground I installed
 
Chris Beauchamp said:
I have confirmed the power to the relay goes away when the key is off... I'm getting 12v backfeeding from somewhere
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Need more detail. At what terminal do you measure 12 V with key off? If the voltage drop from coil+ to coil- (85 to 86 or vice-versa) is zero, the relay should be OFF, regardless of what voltages are applied at the output terminal (usually 87 but could be 30). Often a bad ground can cause strange interactions, since the ground is no longer BAT-.
 
BillGrissom said:
Need more detail. At what terminal do you measure 12 V with key off? If the voltage drop from coil+ to coil- (85 to 86 or vice-versa) is zero, the relay should be OFF, regardless of what voltages are applied at the output terminal (usually 87 but could be 30). Often a bad ground can cause strange interactions, since the ground is no longer BAT-.
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I have 12v at the + post of the coil apparently back feeding somehow...
 
Chris Beauchamp said:
Is a switch required to open the ground for the relay I installed?
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Shouldn't be. The only time I recall seeing coil- to gnd switched (in our cars) is for safety things like the NSS in the starter circuit.

Relays in cars since ~1990 are wired different. One side of the coil is usually hot (12 V, always or from IGN) and the coil low-side is switched to gnd by a transistor to turn on the relay. That is because it is/was easier for a transistor to conduct to ground. Similarly, the 1970+ alternators in A's use low-side switching (actually proportional rather than on-off)? since a transistorized Vreg. Ignition coils have always used low-side switching. Some manufacturers today use high-side switching of a relay coil since as easy to make a transistor for that today, though Mopar stuck with low-side switching.
 
Chris Beauchamp said:
Would a switch interrupting the ground be ok or do I need to locate why it's feeding that 12v?
Click to expand...
The proper approach would be to trouble-shoot to find what is wrong, rather than kludge a fix. I have a relay for underhood IGN power in my 3 1960's Mopars, indeed installed a fuse/relay box for a 1990's Jeep so relays for many things like headlamps, starter, horn, ... I removed the OE relays for those functions on the firewall to reduce clutter.
 
BillGrissom said:
The proper approach would be to trouble-shoot to find what is wrong, rather than kludge a fix. I have a relay for underhood IGN power in my 3 1960's Mopars, indeed installed a fuse/relay box for a 1990's Jeep so relays for many things like headlamps, starter, horn, ... I removed the OE relays for those functions on the firewall to reduce clutter.
Click to expand...
I'll see what I can trace back
 
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