# Understanding A Diagram

Carl Technician Baytown, Texas Posted   Latest   Edited
Question
Electrical
2002 Lincoln Blackwood 5.4L (A) 4-spd (4R100)
No Cruise Control

I don't understand the horn and cruise on switch in this diagram

0
Geoff Diagnostician
Lahaina, Hawaii
Geoff Resolution

Kinda hard without printing them, but you need Diagram 44-2 also. Because, e.g. you press Cruise ON and point "2" becomes "live", and that goes through the clock-spring (Airbag Sliding Contact) to Diagram 44-2. I can probably guess that's a B+ but IDK for sure. Further thinking my example, of "Cruise ON" M87 Speed Control Servo "sees" that input, at pin 5, and "knows" that input means "CC…

+1 Resolution Ð Bounty Awarded
Carl Technician
Baytown, Texas
Carl Default

that's funny. now I need to find A. Is the A inside a triangle a power distribution page?

0 Default Ð Bounty Awarded
Tom Mobile Technician
Chicago, Illinois
Tom Resolution

A goes to the horn switch

0 Resolution Ð Bounty Awarded
Geoff Diagnostician
Lahaina, Hawaii
Geoff Resolution

On Ford diagrams, the A (or B, or C...) inside a triangle, like that, is not a thing, it is for the purposes of making the diagram easier to read.

+1 Resolution Ð Bounty Awarded
Carl Technician
Baytown, Texas
Carl Default

how do I thank everyone and switch to solved from unsolved ?

0 Default Ð Bounty Awarded
Geoff Diagnostician
Lahaina, Hawaii
Geoff Default

Scroll back into your original post section, and Click on EDIT and go from there.....I think.

0 Default Ð Bounty Awarded
Kent Mechanic
Lennox, South Dakota
Kent Resolution

In this case A is just saying it’s the continuation of the wiring diagram. There are two A’s on the diagram.

+2 Resolution Ð Bounty Awarded
Carl Technician
Baytown, Texas
Carl Default

Ok, basically voltage drop to pin 5. 0 voltage drop to turn on .cruise drops voltage thru resistor and so does set/resume, just different voltage drops thru resistors..hum

0 Default Ð Bounty Awarded
Geoff Diagnostician
Lahaina, Hawaii
Geoff Default

Yes. Pin 5 will get different voltages on different button presses. The circuit from the CSM on the new page you found is likely a 5V reference or possible 12v reference. It will most likely give a value on a meter but probably not light a bulb.

0 Default Ð Bounty Awarded
Kent Mechanic
Lennox, South Dakota
Kent Resolution

Horn switch just grounds horn relay to activate horn. Horn is controlled by central security module. Cruise control switches ground through different resistors to change the voltage on cruise signal wire. Fig 4 pin 5 of cruise module. I would check the voltage at pin 5 and see that the voltage changes when each cruise control button is pushed. Then check the brake switch inputs to module. More…

0 Resolution Ð Bounty Awarded
Brian Technician
Bridgewater, New Jersey
Brian Default

That is weird...but without having it in front of me, best I can gather is voltage (or even ground) comes into the steering wheel controls on pin 4. Then there may be a voltage bias for the cruise control "on" button to differentiate between that and the horn. Even without understanding how exactly it works you should be able to check continuity of the switches based on the 1st diagram.

0 Default Ð Bounty Awarded
Tom Mobile Technician
Chicago, Illinois
Tom Default

Pin 6 of the cruise control module supplies the ground for the speed control command switches, and is also the ground for the horn switch circuit. When the horn button is pressed it grounds the dark blue wire at the central security module which then supplies B+ to the horn. If the speed control servo is disconnected the horn will not operate. The only switch that sends voltage to the servo is…

0 Default Ð Bounty Awarded
Hollis Technician
Hollis Resolution

Subaru call's it a Resistive Multiplex Signal (MUX) or a Voltage Dividing Circuit and explains it like this. [***see below] I think that's what your diagrams are illustrating. Check the Theory of Operation and or the General Description for the CAN system of your vehicle. [***A MUX signal is created in the following way. A control module uses a regulated voltage to pass through a fixed…

+1 Resolution Ð Bounty Awarded
Carl Technician
Baytown, Texas
Carl Default

I think I have a bad on off switch for cruise. can I apply 12 volts to my LB/BL signal wire going to my cruise control module to turn cruise on? Isn't that what it does ?

0 Default Ð Bounty Awarded
Kent Mechanic
Lennox, South Dakota
Kent Default

When you back probe lightblue/black wire at cruise control normal voltages should be on battery voltage released 6-7.5v set/accel 4-5v off .5v or less

0 Default Ð Bounty Awarded
Carl Technician
Baytown, Texas
Carl Default

It looks to me , from the diagram, like it receives 12 volts for a second when you push on , on the cruise switch... I have 0 volts when I push on. Ok I had two problems ,imagine that. 1. Gem module had PO500 VSS. it is tied into the cruise module . they both get the signal from the same wire from PCM. unplug cruise module and no longer set code. found used cruise servo module and installed . no…

0 Default Ð Bounty Awarded