Here?

Sorry, I'm being dumb. Didn't I just do that?

 

Just covering the bases before spending money on a SLCM

There is a lost in translation between the 2 different English languages

 

Much more likely my lack of understanding. I do really appreciate your expertise and patience.

There is an outstanding question on whether the SLCM is getting a ground trigger on BT2-1, when I tested this (by measuring resistance between BT2-1 and battery earth strap) I saw no change on brake peddle press where it remains at 18 Ohms at all times, would we not expect this pin to go to close to 0 on peddle press?



In addition I do not see 12v on the relay chip when the brake is pressed, which I believe is the trigger side of the relay for the stop lights.

So it seems the SLCM is not getting the signal from the brake light press?

 

Just occurred to me, does the wiring diagram refer to 2 connectors or is BT1 & BT2 on the same physical connector?

 

Yes they would be 2 separate connectors

Can you identify the wire color orange / green

Socket 1 should be in one of the corners of the connector

It is the same wire that closes the stop lamp relay to give your 3rd brake light . and you have that

unless the wire was cut or bad splice at BTS10

The big connector above the fuel tank as BT4 Pin 18 is a pain to get back reconnected . you have to be careful to not break the lock pins for the lock over bar , there should be a tie wrap on the lock over bar

But is good enough to close the stop lamp relay ,

Using a car frame ground stud is the resistance from socket 2 of the removed relay the same as the resistance at BT2 - 1 with that connector off and the probe on that socket 1

They should be as close as can be to zero

will be out today doing some medical imaging

 

I just double checked and the 2000 is the same as the 2001

The BT! connector is the smaller one to the larger BT2

 

Found the mythical BT2-1 OG wire and tested resistance (battery connected, SLCM disconnected, battery earth strap)



Brake off: no circuit
Brake on - BT2-1: 130 Ohms
Brake on - socket 2 removed relay: 82 Ohms

I guess 82 Ohms is low enough to switch the physical relay, so is the question 'Is 130 Ohms low enough for the ground trigger going into the SLCM and why are they so different?'

 

No , something not right with 130 ohms

Stop lamp relay socket # 2 to car frame ground ( relay removed ) of 82 is still high there but it works to close the relay

This relay is closing since you have the 3rd stop light and this socket # 2 would be a comparison to the BT2 - 1 as they are the same OG wire ground path

The resistance value should be close to zero, but not perfect

The waring out part is the brake switch and there are 2 switches inside 1 brake switch assembly

Pin X and Y

Someone had a excellent picture

Next we will look at the ignition switch ground path , easy

The large BT4 connector pin 18 above the fuel tank OK ? Do not try too hard to close the connector lock over bar

The sheet metal cutout can prevent the connector from closing together fully

 

I enjoyed reading easy.

The large BT4 connector pin 18 above the fuel tank OK ? Check resistance between BT4-18 & BT2-1?

 

BT4-18 & BT2-1?

Yes

Between the 2 points in this segment should be zero resistance

this wire segment is not looking at the brake switch or ignition switch

 

If it gets to it here is some info on the brake switch

Brake Light Switch - Jaguar Forums - Jaguar Enthusiasts Forum

And the ignition switch , just the small U shape cover comes off under the steering column and the switch does not need to be remove but just the 5 wire connector 6 inches away

If the ignition switch is bad it separates from the key barrel, so no new key needed

Easy again

Your pins on the ignition switch connector with the connector removed are 3 and 5 with the key rotated to the run position

This pin 3 is deferent then the key rotation position 2 on the print



Editing

 

Struggling to find pin #'s

 

That one is different then mine

Can you isolate the OG color wire?

Ford changed over some of the connector parts, and someone posted a connector part # list PDF to reference this one item

Again # 1 should be in the corner of the 4 possibilities and this excludes the 6 larger high current pins / sockets as those are labeled as A , B , C and on

look for a socket being pushed back not able to make contact

You can tug on the OG wire to see if it is locked in place to make good contact

 

I'm guessing at pin #'s but it works out for an OG wire on 18 (there are 3 OG wires).

Assuming I've found the correct OG and pin #18 then BT4-18 has great continuity to BT2-1 (0.2 - as good as meter prob to prob)

 

Looking

Excellent pics

 

I'm guessing at pin #'s but it works out for an OG wire on 18 (there are 3 OG wires). Assuming I've found the correct OG and pin #18 then BT4-18 has great continuity to BT2-1 (0.2 - as good as meter prob to prob)

So now you need to look forward

The ignition switch should be the same and can be checked easiest

look for corrosion in the ignition switch connector

The pin 5 on the car side of the connector half is a car frame ground and this can get disturbed if tinkering behind the dash

The car side half of the connector lifts straight up to remove from the mount to bring the work out to you

So you want to read the pin 5 car side half resistance to car frame ground , the switch is out of the picture in this section

Next we will be looking at the switch side half of the connector

 

Thank you. Will be tomorrow now, dark and cold again.

 

Definitive proof would be BT4 pin 18 resistance to car frame ground with the brake pedal depressed and not depressed

This should go to zero resistance to trigger brake light illumination , high resistance for brake light off

This would be car side forward half of tghe BT4 connector

 

Looking at the diagram, it looks like the brake switch will only go to ground when pressed if the ignition switch is in position ii, correct?

 

Yes