The Stovebolt Site Forums The Shop Area The Electrical Bay Ammeter, ignition wiring

Well, the curved 8-wire connector on the column and the flashers all work correctly, thanks to all who helped. In the course of working on the speedo, I disconnected everything from the instrument cluster, and even labelled the wires to the ammeter. When I put everything back, I nearly burned the truck up. Obviously I screwed up, and it involves the four wires to the ammeter.The four wires are one to the alternator (one-wire alternator), one to the BATT screw on the ignition switch, one to the big lug on the starter, and one full-time hot to the light switch and horn. I know these are connected as two pairs (not one and three). Which two go to the discharge side of the ammeter (left), and which go to the charge side (right)?

Russell,

My guess would be the alternator and lights tied together on the - post of the ammeter and the starter and BATT connected to the + post. You say they are connected in pairs...had you not mentioned this, I would have put the BATT wire together with the ALT and lights on the - side.

For the ammeter to show charge/discharge activity properly, any load must come off the - side of the meter.

Stuart

Yeah, I'm with atomarc on this one. Are you absolutely sure they go 2 and 2? I would've put only 1 wire on the + side of the ammeter and that one would go to the starter terminal (which is your hot lead from the battery) Everything else (I would think) would connect to the - side of the ammeter. In lieu of this, what atomarc suggested is the next best alternative but I don't think your ammeter would read all the discharge in this mode.

Even if you wired the ammeter wrong, it should not cause a fire unless a ground wire was involved or one of the wires or ring terminals shorted to ground. Otherwise it just won't read correctly if miswired. I guess I am saying that you may still have a problem.

Yep! I agree with Baldy too. (ain't we just all getting along good together today?) I don't see how any combination of these 4 wires connecting to the ammeter would cause what you describe.

Russell mate Baldy is on the money here ,i have just seen this post so i am sorry for that,but if you have a read of my reply to Gazim/Joker in this forum topic was "electrical woes" hope it helps

Update on the situation. First of all, the burned wires happened after I connected the ammeter, and while I was tinkering on the heater motor with power on. The liklihood that something just shorted out, with no relationship to the ammeter is strong. I have reviewed all the responses on this post (thanks for all input), and am going cross-eyed studying the wiring diagram from the factory assembly manual. The diagram shows one wire going to the positive side of the ammeter--12 ga black from the starter. It shows two wires going to the negative side of the ammeter- one is 14 ga red to the BATT terminal on the ignition switch, the other is 12 ga red which splits to feed the headlight switch and also connects to the B terminal on the voltage regulator. Since I don't have a voltage regulator, I am assuming the single wire from my alternator goes to ammeter negative, the same as the voltage regulator one would. With things connected in this fashion, the ammeter needle shows a strong 'charge' when I crank the engine. Shouldn't it show a strong 'discharge' when cranking?? The engine won't start, so I can't see what happens then--whole different issue !

In addition, the horn doesn't work, and I am certain the problem is the relay. It is the original relay, and is either defective or wired wrong. While attaching and removing the three-prong adapter, I can hear and feel the contacts moving inside. With the relay connected, and the horn button at the ready, there is power to the red power supply (as there should be), and power to the horn button lead. Pressing the horn button doesn't affect power to the lead. Is the relay defective, or are the black and tan wires to the horn and button reversed?

You won't see a strong discharge on the ammeter while cranking because the starter is wired directly to the battery and that current doesn't go through the ammeter. It's possible that the alternator is supplying current at crank speed, which would show as a positive.

The horn button should ground the wire to the relay, and if it doesn't, the relay won't work. You could ground that wire at the relay to see if that blows your horn, but you have to determine why your horn button isn't supplying ground when depressed.

Russell,

The relay has (I think) three terminals. You have already identified one correctly, that's the power wire for the horn itself. That power wire is part of a normally open contact inside the relay. A small internal jumper grabs some of this power and applies it to the coil that closes the relay to power the horn. The relay coil has power, but is insulated and has no ground. The third terminal is that ground..which is completed when you mash the horn button down.

So you can see that there should only be voltage on the terminal connected to the battery...the power wire, not on any other terminals. The relay should do nothing when the connector is removed or attached.

I think the relay is toast. No terminal should have continuity with any other terminal except when tooting the horn. You are doing a excellent job troubleshooting and explaining these problems...keep it up. Sorry for the mini-novel on such a little relay.

PS..The horn could be in 'auto-toot'. Pull the wire that goes to the horn button then remove and reattach the power wire and listen for clicking contacts. If this kills the clicking, the horn wire is grounded somewhere and the horn is dead, or the contacts are burnt and not passing power to the horn.

Stuart

Actually, you will see the full V+ at the horn button wire. It comes through the coil of the relay and requires very little current to overcome when the button is depressed to supply ground to the coil.

Baldy,

That makes sense...I stand corrected, thanks.


Stuart