Lynx scout car wiring problems (Ford)

[rob love]

I'm looking at the resiter package on ours now and it has the screw in the top corner. No idea why it does not ground.

It is wire no 22 for the temp gauge according to my manual. Wire 20 is for the LH fuel sending unit to the fuel gauge switch.

I have a job on the go today, but hopefully I'll find some time in the next day or two to pull the guard and do some circuit checking. My wire 22 is coming from the right side of the circuit divider. I should think the coil would be what came off the small resister.

When I re-wired the lynx, I remember thinking it was funny that they ran 12 volts from the engine compartment all the way up to the dash, to then run the 12 volts back to the divider and then run it back up to the front again and twice at that. Once for the 6 volt electrical gauge, and once for the remainder of the gauges. I am running a 12 volt gauge so have the one extra wire tied off at the divider unit.

I note that where your wire 20 (22?) comes off the resister now, it might as well be off the screw one lower. There is no voltage drop from the bottom resister to the terminal that wire is coming from. If the mounting screw was fastened to the top corner and grounded out, it would merely burn out the top resister....it would not effect the voltage at the first terminal. Of course, the race would be what burns out first...the top resister, the bottom resister, the circuit breaker, or some piece of wiring.

More to follow.

[Colin Alford]

Gents,

I am certainly not an electrical engineer and unlike the three of you, I have never even touched a Ford Lynx.

I do however have access to SC-F3 and a few months ago I was seriously studying the wiring diagrams to help diagnose a "no power to coil" issue in a Windsor Carrier which uses many of the same electrical components.

I am surprised that there appear to be so many different versions of the wiring diagram. It appears that Peter's image is the same as that on page N-1 of SC-F3 so I presume that it is his source. Rob/Rick - What manuals are you referencing?

I have attached a few images from SC-F3 but I find that I struggle trying to get decent resolution in the images but keep them small enough to attach to a post.

On page N-2 of SC-F3 there is a second wiring diagram that I think will be most useful to this conversation. This type of diagram probably has a proper name but of interest is that it shows the voltages, resistances and grounding points.

It shows a ground point at the 6 volt side of the voltage divider. Is this the proof to alleviate Rick's concern about a potential short circuit caused by the mounting bolt passing through the top end of the voltage divider? (again I am not an electrical engineer and understand Rick's concern)

Page N-3 has an image of the voltage divider in-situ in the vehicle and should help determine which wire connects to which terminal.

I have also included a close-up of the circuit breaker/voltage divider and the other half of the legend from the diagram on page N-1 of SC-F3 to complement Peter's images

If any of you would like higher resolution pictures please send a PM with your email address and I can send them to you

[Mike K]

Rick

I think you have misunderstood the circuit . If you study the wiring diagram, the coil 4 Volts feed comes off the larger resistor . The smaller resistors feed the instruments . Mike

[Colin Alford]

Rick,

I will echo Mike's comment that I think you previously misunderstood which components were performing which task on the Circuit Breaker/Ignition Resistor/Voltage Divider assembly.

I think if you have a good study on the newly provided wiring diagrams that it should make sense (I can send higher resolution images if you would like).

I have also sorted out the question of the mounting bolt providing a path to ground and therefore a short circuit. The mounting bolt is designed to provide the ground and therefore make the Voltage Divider work! I really had no idea how this functioned until I googled "Voltage Divider"

See:
https://en.wikipedia.org/wiki/Voltage_divider

[Peter Duggan]

Rick,

Thanks for raising this question about the mounting of the circuit breaker assembly. I was mistaken about how it functioned and how it should be mounted.

Colin, Mike and Rob,

Thanks for sharing your time and knowledge. These are the benefits that I was seeking when I first joined this forum. A great group of people.

Thanks again, Peter

[lynx42]

Thank you Peter, Rob, Mike and Colin. We're getting somewhere. I was completely stumped at the start but now seem to understand a bit better.(??)

I have sent you a PM Colin, for better resolution copies of the SC-F3 wiring system.

The early Lynx manual Sc-F1 and F2,(mine) is hard to understand and as well, all wires are BLACK and not numbered.

Thanks again, I knew MLU members would come up with the answers.
Regards Rick.

[lynx42]

Next question, what is with all the condensers on everything and filters as well. Is it necessary to have every one or can the vehicle operate without some of them?

Can I use any old (new) condenser or do they have a rated action?

I guess that they are there to cut down radio interference etc, so are they really necessary if I am not using a working WWII radio? I have a No.11 fitted but it is only there for looks.

Regards Rick.

[Tony Wheeler]

Originally Posted by Mike Kelly

If you study the wiring diagram, the coil 4 Volts feed comes off the larger resistor . The smaller resistors feed the instruments .

Exactly.

Lynx resister unit 013.jpg

I notice one wiring diagram is for ammeter and the other is for battery condition indicator (ie. voltmeter). It's optional of course but something to be aware of when wiring up.