Cromagnon
SILVER Star
You should be able to ohm the IG terminal and see if it is a short to ground. I would think it would have a some ohms if it is good. Just make sure to disconnect the battery and the BY wire.
1975 FJ40 Instrument Panel Not Working (3 Viewers)
- Thread starter Groucho263
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- Thread starter
- #62
Was not using the wiring diagram, just reporting how the wiring was in the vehicle. The BY wire from the VR is about 18 guage...it y's and goes to the fuse panel then towards the battery under the dash. It has the 'factory' 2 into 1 connector so it looks like it's supposed to do that? There is a similar size BY wire going into the Ignition Coil. I'm assuming this is the same one.
The bigger 12ish guage BY wire is the other one you are describing...I think . It goes from the fuse panel in 2 locations and goes into a factory connector into 1 wire. This goes to the ignition switch. See pictures:
The bigger 12ish guage BY wire is the other one you are describing...I think . It goes from the fuse panel in 2 locations and goes into a factory connector into 1 wire. This goes to the ignition switch. See pictures:
Cromagnon
SILVER Star
Was not using the wiring diagram, just reporting how the wiring was in the vehicle. The BY wire from the VR is about 18 guage...it y's and goes to the fuse panel then towards the battery under the dash. It has the 'factory' 2 into 1 connector so it looks like it's supposed to do that? There is a similar size BY wire going into the Ignition Coil. I'm assuming this is the same one.
Well according to the wiring diagram I have, only the voltage regulator is fed from the fused BY not the ignition coil.
The ignition coil and the Ignitor is fed from the BY wire coming from the ignition switch, that could account for the splice tap. That BY is also feeding the "switched" fuses in the fuse panel.
The PO may have used the BY from the ignition switch thinking that a BY is a BY. Is there another BY laying loose in the wire bundle that is fed from the fuse panel?
Well according to the wiring diagram I have, only the voltage regulator is fed from the fused BY not the ignition coil.
The ignition coil and the Ignitor is fed from the BY wire coming from the ignition switch, that could account for the splice tap. That BY is also feeding the "switched" fuses in the fuse panel.
The PO may have used the BY from the ignition switch thinking that a BY is a BY. Is there another BY laying loose in the wire bundle that is fed from the fuse panel?
- Thread starter
- #64
Well. Here is the result. FYI...I have a ground from the starter to the chassis. Going to clean those connections now but it has battery to frame...alternator to frame and starter to frame grounds
BY wires...the BY wire that was going to the VR connected via aY connector one end went to the fuse panel the other went into the main wire bundle. It Y’d into a BY and a B wire that could be left over emission wires but they do not go to the ignition coil. So, I used some BY wire and ran it directly from the VR to the Engine 15A fuse. Started the engine and blew the 15a fuse again. And...alternator putting out 12.2 volts. So that didn’t work. Why is that 15a Engine fuse blowing?
New VR isn’t here yet...so haven’t tested that.
BY wires...the BY wire that was going to the VR connected via aY connector one end went to the fuse panel the other went into the main wire bundle. It Y’d into a BY and a B wire that could be left over emission wires but they do not go to the ignition coil. So, I used some BY wire and ran it directly from the VR to the Engine 15A fuse. Started the engine and blew the 15a fuse again. And...alternator putting out 12.2 volts. So that didn’t work. Why is that 15a Engine fuse blowing?
New VR isn’t here yet...so haven’t tested that.
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Cromagnon
SILVER Star
Ohm the voltage regulator IG terminal to the case. If it is less than a couple of Ohms then the VR is bad. That would account for the fuse blowing.
- Thread starter
- #66
Ohms at the voltage regulator, the BY connection is basically 0 (it initially measured about 14ish then settled at 0). I'm not sure I measured it correctly though. At the fuse panel, I couldn't get any Ohms to measure for any wire going into the fuse panel. Battery was disconnected.
At the voltage regulator, the WG wire was basically the same as the BY which is why I am not sure I did it correctly.
At the voltage regulator, the WG wire was basically the same as the BY which is why I am not sure I did it correctly.
Cromagnon
SILVER Star
Disconnect the BY and WG wires from the voltage regulator when you do the measurement. Measure from IG to ground and IG to WG.
If you look at the diagram and video HERE, it will explain the voltage regulator circuit and what it is doing as the charge changes. If the resistor has burned and shorted to ground (or any short to ground in the voltage regulator) that will cause your blown engine fuse. If there is a resistance here then hook up the WG wire and redo the measurement from IG to ground and IG to WG.
If you look at the diagram and video HERE, it will explain the voltage regulator circuit and what it is doing as the charge changes. If the resistor has burned and shorted to ground (or any short to ground in the voltage regulator) that will cause your blown engine fuse. If there is a resistance here then hook up the WG wire and redo the measurement from IG to ground and IG to WG.
- Thread starter
- #68
IG to ground = 0 Ohms
IG to WG = .10 Ohms
IG to WG = .10 Ohms
- Thread starter
- #69
New VR is here and is the exact same one I had with the exact same Ohms. Thinking it was maybe the wires, I hooked up 2 new wires directly from the alternator to the VR (straight across the engine) and same volts from the Alternator...12.10. Cleaned the ground wire from the starter to the frame...no change. So at this point, even though Napa says the alternator is putting out 14.9 volts, I'm at a loss.
Cromagnon
SILVER Star
When you hooked up the voltage regulator with the new wires did the engine fuse pop again?
- Thread starter
- #71
Hooked the new VR up to the old wires and just when I said, well...at least it didn't fry the fuse, it fried the fuse. I will try another fuse with the new wires and report back. If the old wires were shorted in the main bundle, that might cause the fuse to blow, correct? That's what I was trying to test with the new wires, I just didn't hook up the engine fuse.
Cromagnon
SILVER Star
That is correct. There must be a wiring issue but I would think bypassing the harness and wiring the alternator direct like you have already done would eliminate any issue the harness may have.
- Thread starter
- #73
Fuse still blows with wires direct from VR to Alternator...WG and WB...BY from VR to fuse panel. Alternator is consistently putting out between 11.57 - 12.10 volts. The fuse is blowing because it's getting more current than the 15A fuse can handle. I don't think it's the VR since this is the second one and almost exact same as the first. The alternator never shows more than 12.10V so the VR doesn't have to close (or open) the connection if it's getting more than 14.4 ish so there should not be an over current situation going to the fuse. I have had the fuse panel disconnected from the vehicle so I could access the wires/clean the connections, etc. Does the fuse panel need to be connected to the frame in order to ground? Pretty close to wits end.
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- Thread starter
- #74
@Marn0 you were on the right track.
So...for anybody who has the same issue in the future, we solved the problem of the Alternator not charging. We had the WB and WB wires backwards. This picture is the old wire routing...switch WG and WB and the alternator is putting out up to 14.7 V and the engine fuse is not blowing any longer.
Now, to figure out why the gauges in the speedo aren't working...and get the lights to work (to include brake lights). I'll keep posting as I figure it out.
So...for anybody who has the same issue in the future, we solved the problem of the Alternator not charging. We had the WB and WB wires backwards. This picture is the old wire routing...switch WG and WB and the alternator is putting out up to 14.7 V and the engine fuse is not blowing any longer.
Now, to figure out why the gauges in the speedo aren't working...and get the lights to work (to include brake lights). I'll keep posting as I figure it out.
- Thread starter
- #75
My LR wire that says 12 Volt from Ignition key goes from the speedo cluster to the main harness out the passenger side with the main harness and down along with the speedo cable. Is this wire supposed to connect somehow to the Ignition coil or POS battery?
Cromagnon
SILVER Star
The LR comes from the switched side of the fuse panel and feeds several circuits including the blower motor, backup light switch, and the seat belt relay (if you have that). If it is goimg out the pax side that may be going to the blower motor.
- Thread starter
- #77
There is actually 2 LR wires that I want to make sure to differentiate. There is a 14 (maybe 12) gauge wire that is the 4th fuse down on the fuse panel. The 5th fuse down on the fuse panel is also a LR but is closer to the 16 gauge size. The one from the speedo cluster is smaller like an 18. The LR wire coming out the passenger side goes under and aft on the vehicle. I'll try to follow it tomorrow, but it doesn't go to the blower. That's a LW wire. Is there supposed to be a LR wire from the fuse panel to the speedo to power the oil press, temp, gas gauge, etc.?
Cromagnon
SILVER Star
Yes, coming from a switched side fuse (one that has power when the ignition is on.) It should also power the reverse light switch, the heater and the seat belt relay. The fuse may be labeled "Heater."
It didn’t sound like the field was getting any excitation
Cromagnon
SILVER Star
There is a LR that goes to the rear heater motor that could go under the tub. That is the only LR wire on the wiring diagram that I have for 75 or 79 that goes towards the rear of the vehicle.
