66 Barracuda gauge problems
The same Master Tech Conference has sessions on how to read the wiring diagrams.
Lets look at the '66 Plymouth FSM.
The dashed lines represent the instrument panel.
Wires are identified by a code. G is for Gage. Number is the circuit and a letter, if present, is a branch.
In the key is the wire color and SAE wire gage. So G1 is 18 gage black, and my guess is that is the power supply from the key switch. Lets look.
Yes it its.
How do we read this? The circles represent junctions. Usually they are solid circles but for whatever reason in this case the welded junctions are larger open circles. Wire G1 joins wire Q2 coming from the ignition switch.
J1 is the feed into the key switch. Its always hot and by accepted convention the connections are marked Batt or B or Battery. Don't let this fool you into thinking it comes direct from the battery. It comes from a junction joining the battery (wire R6A) and the alternator output power (wire R6) to the main feeds. Lets color these in.
When the key is in Run, there is power at the switched accessory terminal as well as the ignition run terminal.
Lets color those in. (even better sometimes is to redraw the circuits we're interested in on apiece of paper)
Now lets go back to the instrument panel connector.
G1 brings power in. We call it 12 Volts (even though its really close to 14.5 V when the engine is running)
The solid dots represent the connected terminals.
12 Volts is available at the Fuel gage. Inside the gage it connects to the IVR.
From the IVR reduced (pulsating) power is available to the fuel gage resistance wire.
Via the circuit board it the the IVR power is available to the termperature gage.
It seems the IVR feed to the oil gage on the other board is incorrectly marked "Oil and Temperature Gage". I would guess that confused things.
The only thing wire G3 feeds is the oil pressure gage.
The same Master Tech Conference has sessions on how to read the wiring diagrams.
Lets look at the '66 Plymouth FSM.
The dashed lines represent the instrument panel.
Wires are identified by a code. G is for Gage. Number is the circuit and a letter, if present, is a branch.
In the key is the wire color and SAE wire gage. So G1 is 18 gage black, and my guess is that is the power supply from the key switch. Lets look.
Yes it its.
How do we read this? The circles represent junctions. Usually they are solid circles but for whatever reason in this case the welded junctions are larger open circles. Wire G1 joins wire Q2 coming from the ignition switch.
J1 is the feed into the key switch. Its always hot and by accepted convention the connections are marked Batt or B or Battery. Don't let this fool you into thinking it comes direct from the battery. It comes from a junction joining the battery (wire R6A) and the alternator output power (wire R6) to the main feeds. Lets color these in.
When the key is in Run, there is power at the switched accessory terminal as well as the ignition run terminal.
Lets color those in. (even better sometimes is to redraw the circuits we're interested in on apiece of paper)
Now lets go back to the instrument panel connector.
G1 brings power in. We call it 12 Volts (even though its really close to 14.5 V when the engine is running)
The solid dots represent the connected terminals.
12 Volts is available at the Fuel gage. Inside the gage it connects to the IVR.
From the IVR reduced (pulsating) power is available to the fuel gage resistance wire.
Via the circuit board it the the IVR power is available to the termperature gage.
It seems the IVR feed to the oil gage on the other board is incorrectly marked "Oil and Temperature Gage". I would guess that confused things.
The only thing wire G3 feeds is the oil pressure gage.