LSM wiring diagram - Page 2

Phil-T4 · 2nd October 2016, 20:39

I suppose you have checked Fuse 7 which supplies power to the switches?

bigblue75 · 3rd October 2016, 11:38

Original thread
http://www.the75andztclub.co.uk/foru...d.php?t=253273

Checked all fuses for continuity, all good
checked all bulbs, all good
cleaned connectors at ABS module, LSM, break light switch, all rear lights

Switch working perfectly at ignition position 1 with ABS fuse (32) in place AND in all positions when ABS fuse (32) removed.

I think the switch ( LEMARK LBLS113 ) is working correctly,
I think something is causing the system to read the switch as being pressed when

The ABS fuse (32) is in place AND the ignition is at position 2 or 3.

Will try to get the car to Dunc as soon as possible, thought a diagram of the LSM connector might keep me busy til then.

chgperformance · 4th October 2016, 19:31

Out of curiosity, measure the voltage on the pin at the LSM from the switch with the ignition on position 2 and the fuse in. I had around 7.3v which is too high. Indicating a short somewhere.

bigblue75 · 5th October 2016, 18:31

Did you check the voltage when in position 1?
Not had time to look at anything else, should be able to check this tomorrow.

Is this the green/purple wire fron pin 4 of the switch?

bigblue75 · 6th October 2016, 17:46

Had a chance to take some readings off the wire that goes from pin4 of the brake switch to the LSM (green/purple) using a fine pin through the wire, around 100mm from the connector block.

(pos3 is engine running), all values in volts, ground at base drivers side A pillar
Results were

Fuse 32 removed and pedal not pressed pos0 0.47 pos1 0.90 pos2 1.47 pos3 1.73
Fuse 32 removed and pedal pressed pos0 0.47 pos1 5.40 pos2 5.90 pos3 6.70

Fuse 32 present and pedal not pressed pos0 0.48 pos1 0.92 pos2 4.14 pos3 4.95
Fuse 32 present and pedal pressed pos0 0.48 pos1 5.36 pos2 8.30 pos3 9.75

The brake lights function correctly off the the brake pedal WHEN fuse 32 is removed OR on pos 0 and 1 when fuse 32 is present.

No continuity from pin4 to ground when fuse 32 was in or out.

Does this help make sense of the fault to anybody?

3rd October 2016, 11:38	#12
bigblue75 older not wiser 75 Tourer Join Date: Oct 2014 Location: Falkirk Posts: 274 Thanks: 93 Thanked 46 Times in 35 Posts	To help you to help me Original thread http://www.the75andztclub.co.uk/foru...d.php?t=253273 Checked all fuses for continuity, all good checked all bulbs, all good cleaned connectors at ABS module, LSM, break light switch, all rear lights Switch working perfectly at ignition position 1 with ABS fuse (32) in place AND in all positions when ABS fuse (32) removed. I think the switch ( LEMARK LBLS113 ) is working correctly, I think something is causing the system to read the switch as being pressed when The ABS fuse (32) is in place AND the ignition is at position 2 or 3. Will try to get the car to Dunc as soon as possible, thought a diagram of the LSM connector might keep me busy til then.

6th October 2016, 17:46	#15
bigblue75 older not wiser 75 Tourer Join Date: Oct 2014 Location: Falkirk Posts: 274 Thanks: 93 Thanked 46 Times in 35 Posts	readings Had a chance to take some readings off the wire that goes from pin4 of the brake switch to the LSM (green/purple) using a fine pin through the wire, around 100mm from the connector block. (pos3 is engine running), all values in volts, ground at base drivers side A pillar Results were Fuse 32 removed and pedal not pressed pos0 0.47 pos1 0.90 pos2 1.47 pos3 1.73 Fuse 32 removed and pedal pressed pos0 0.47 pos1 5.40 pos2 5.90 pos3 6.70 Fuse 32 present and pedal not pressed pos0 0.48 pos1 0.92 pos2 4.14 pos3 4.95 Fuse 32 present and pedal pressed pos0 0.48 pos1 5.36 pos2 8.30 pos3 9.75 The brake lights function correctly off the the brake pedal WHEN fuse 32 is removed OR on pos 0 and 1 when fuse 32 is present. No continuity from pin4 to ground when fuse 32 was in or out. Does this help make sense of the fault to anybody? Last edited by bigblue75; 6th October 2016 at 17:55.. Reason: clarity

2nd October 2016, 20:39	#11
Phil-T4 I really should get out more....... MG ZT-T, Rover 75 Tourer Join Date: Mar 2011 Location: Olney Posts: 2,969 Thanks: 245 Thanked 1,088 Times in 657 Posts	I suppose you have checked Fuse 7 which supplies power to the switches?

4th October 2016, 19:31	#13
chgperformance Avid contributor MG ZT-T Join Date: Feb 2016 Location: Wisbech Posts: 168 Thanks: 16 Thanked 29 Times in 22 Posts	Out of curiosity, measure the voltage on the pin at the LSM from the switch with the ignition on position 2 and the fuse in. I had around 7.3v which is too high. Indicating a short somewhere.

5th October 2016, 18:31	#14
bigblue75 older not wiser 75 Tourer Join Date: Oct 2014 Location: Falkirk Posts: 274 Thanks: 93 Thanked 46 Times in 35 Posts	Did you check the voltage when in position 1? Not had time to look at anything else, should be able to check this tomorrow. Is this the green/purple wire fron pin 4 of the switch?