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Old 27th June 2020, 18:18   #1
goltho
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Default Wiring diagram - advice please (photos)

I've put on a few posts recently with similar questions. Ignore them all. This is the Final Question to complete my cruise control retrofit. Jamie Welch handsomely configured my ZT with T4 this morning - thanks again. I got a clean bill of wiring health but there is a brake switch wiring conundrum preventing it from working which I need someone's knowledge about. Please refer to the two diagrams in conjunction with the issue.

Context
• My KV6 was built without cruise and interlock
• The brake switch has all four wires connected
• Header C0285 is missing from the car. That mostly makes sense as it deals with interlock, cruise and parking sensors, none of which my car has
• The green/red (GR) wire from the brake switch pin 3 (C0775-3) is connected to the electronic auto transmission (EAT) pin 43 (C0932-43) in line with its pre-cruise state. It currently functions exactly the same as the wire from C0775-4 which controls the brakes lights i.e. power appears when the brake pedal is depressed. I do not know if it would function this way if the car was OEM-fitted with cruise as there may be two switch types (one is referred to at Rimmers as double pole, and is shown (only once) on a wiring diagram as double pole).
• Whilst T4 confirms the brake lights functioning correctly from C0775-4, it however reports the brakes being permanently on based on C0775-3. This is despite both pins C0775-3 and -4 behaving identically. This alone appears to be preventing cruise from working.
• Pin 6 on the cruise control relay (C0895-6) requires to be connected to C0775-3; in the absence of header C0285, I piggybacked off the EAT C0932-43 as above, to C0895-6. The GR wire colours are also consistent. I am however now doubting whether this is correct based on the attached diagrams.

Wot I need help with
• I do not know if the OEM brake switch is double-pole. It's only shown once in the entire ZT wiring diagrams as being double-pole and is not shown as such on the attached diagrams. Might this be making any difference to how pin 3 behaves - perhaps open when pin 4 is closed and vice versa?
• Should I disconnect the EAT C0932-43 from the brake switch C0775-3 now that cruise is fitted? I'm unable to interpret the diagram in that respect.
• Finally, the smaller of the two attached diagrams shows C0932-43 being connected twice to the missing C0285 (pin 2 and pin 3). Given that there is no interlock fitted, is it again safe to assume that I can disconnect the brake switch C0775-3 from EAT C0932-43 altogether and instead connect it directly to the cruise relay C0895-6?

That's what my brain took me before I wrote this down, and it still arrives at the same point.

I realise wiring isn't everyone's bag but it's straightforward for others. I've always had a good knowledge but have limitations. Someone more qualified help will be hugely appreciated. Thanks in advance.

Dougie.



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Old 28th June 2020, 10:23   #2
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Default

So this is the only reference I can find to the brake switch which shows it as a double pole unit. I'm stlll unable to determine what this means in terms of how it operates. All the evidence suggests I have a single-pole unit.

Pin 1 is from fused power
Pin 2 is to earth
Pin 3 is to cruise relay
Pin 4 is to brake lights

???

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75 2.0 CDTi Connoisseur SE 160bhp + Synergy 2
• Built 11/10/2004 @10:22 hrs
• 104,984/112,381
• 3,398/4,744
• 55/407 Ski Blue (JHI)

––––––––––––––––––––––––––––––––––––––––––––––––––
ZT 180+ Sports Auto
• Built 18/06/2002 @11:54 hrs: Registered 13/01/2003
• 4,906/18,894
• 206/813 Le Mans Green (HPD)

Last edited by goltho; 28th June 2020 at 10:26..
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Old 28th June 2020, 11:18   #3
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Quote:
Originally Posted by goltho View Post
Wot I need help with
• I do not know if the OEM brake switch is double-pole. It's only shown once in the entire ZT wiring diagrams as being double-pole and is not shown as such on the attached diagrams.
Hi Dougie,

The internal detail of the brake pedal switch in your diagrams is unofficial as far as I can tell. RAVE doesn't include it so it may or may not be correct.
Quote:
Originally Posted by goltho View Post
• Should I disconnect the EAT C0932-43 from the brake switch C0775-3 now that cruise is fitted? I'm unable to interpret the diagram in that respect.
RAVE says that C0932-43 is an input to the EAT ECU from the brake pedal switch. In other words, it tells the automatic transmission when the driver is braking. I'd say that you should not disconnect it!
Quote:
Originally Posted by goltho View Post
• ... is it again safe to assume that I can disconnect the brake switch C0775-3 from EAT C0932-43 altogether and instead connect it directly to the cruise relay C0895-6?
It appears to me as if C0775-3 needs to be connected to both the EAT ECU C0932-43 and the cruise relay C0895-6 (both are inputs from the brake pedal switch).

Simon
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Old 28th June 2020, 12:57   #4
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Originally Posted by SD1too View Post
Hi Dougie,

The internal detail of the brake pedal switch in your diagrams is unofficial as far as I can tell. RAVE doesn't include it so it may or may not be correct.

RAVE says that C0932-43 is an input to the EAT ECU from the brake pedal switch. In other words, it tells the automatic transmission when the driver is braking. I'd say that you should not disconnect it!

It appears to me as if C0775-3 needs to be connected to both the EAT ECU C0932-43 and the cruise relay C0895-6 (both are inputs from the brake pedal switch).

Simon
Hi Simon,

All the diagrams are from Rave including the exploded brake switch one.

C0932-43 is indeed an input from C0775-3, and it works. I agree that disconnecting the EAT on that basis, isn't logical. In any case, I disconnected C0932-43 and tried connecting F0775-3 direct to the cruise relay C0895-6 but it made no difference.

So I'm left with with the question of why there are two OEM brake switches available, one double pole and one single pole, and why T4 was reporting cruise control as believing the brakes are on permanently.

Dougie.
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• Built 11/10/2004 @10:22 hrs
• 104,984/112,381
• 3,398/4,744
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• Built 18/06/2002 @11:54 hrs: Registered 13/01/2003
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• 206/813 Le Mans Green (HPD)
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Old 28th June 2020, 12:57   #5
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Hi Doug, yes the internal detail of the double pole brake switch is shown on the exterior brake and reverse lamps part of my wiring diagrams too



I've checked the supercession lists on my EPC, and the original white double pole brake switch has now been replaced with XKB000022A, so a cheaper Land Rover alternative is XKB000022

So I would start by making sure the switch fitted to your car is the correct one, then take it from there

Brian
Attached Images
File Type: jpg double pole switch.jpg (127.2 KB, 80 views)
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Old 28th June 2020, 13:06   #6
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Quote:
Originally Posted by marinabrian View Post
Hi Doug, yes the internal detail of the double pole brake switch is shown on the exterior brake and reverse lamps part of my wiring diagrams too

https://the75andztclub.co.uk/forum/a...1&d=1593344863

I've checked the supercession lists on my EPC, and the original white double pole brake switch has now been replaced with XKB000022A, so a cheaper Land Rover alternative is XKB000022

So I would start by making sure the switch fitted to your car is the correct one, then take it from there

Brian
I'm collecting an XKB000022A tomorrow morning from Rimmers which I ordered yesterday after the T4 session. They also stock the XKB000022 but I can't see any spec difference. Neither are described as double-pole whereas XKB000090 is (https://rimmerbros.com/Item--i-XKB000090).

Do you read the switch as needing to be double-pole?

Quote:
Originally Posted by marinabrian View Post
I've checked the supercession lists on my EPC, and the original white double pole brake switch has now been replaced with XKB000022A, so a cheaper Land Rover alternative is XKB000022
According to an older thread, the Land Rover switch isn't compatible.

https://the75andztclub.co.uk/forum/s...3&postcount=14

Dougie.
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• Built 11/10/2004 @10:22 hrs
• 104,984/112,381
• 3,398/4,744
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––––––––––––––––––––––––––––––––––––––––––––––––––
ZT 180+ Sports Auto
• Built 18/06/2002 @11:54 hrs: Registered 13/01/2003
• 4,906/18,894
• 206/813 Le Mans Green (HPD)

Last edited by goltho; 29th June 2020 at 00:31..
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Old 28th June 2020, 13:32   #7
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Quote:
Originally Posted by goltho View Post
I'm collecting an XKB000022A tomorrow morning from Rimmers which I ordered yesterday after the T4 session. They also stock the XKB000022 but I can't see any spec difference. Neither are described as double-pole whereas XKB000090 is (https://rimmerbros.com/Item--i-XKB000090).

Do you read the switch as needing to be double-pole?

Dougie.
The switch needs to be double pole, and to be fair the XKB000022 is listed for the L322 so that will be an auto, and it will be fitted with cruise, and I suspect the correct double pole switch.

The original part number prior to supercession is as follows

XKD000010

Description

Switch-stop/cruise brake - White, double pole C



And the following applies to the supercession XKB000022 switch

Product Description

Up to VIN 5D345691 the brake light switch may have been coloured white for cars with cruise control fitted but this black switch is now suitable for those applications.

Brian
Attached Images
File Type: jpg brake pedal switch.jpg (71.3 KB, 61 views)
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Old 28th June 2020, 14:27   #8
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Quote:
Originally Posted by marinabrian View Post
The switch needs to be double pole, and to be fair the XKB000022 is listed for the L322 so that will be an auto, and it will be fitted with cruise, and I suspect the correct double pole switch.

The original part number prior to supercession is as follows

XKD000010

Description

Switch-stop/cruise brake - White, double pole C
https://www.the75andztclub.co.uk/for...9&d=1593347180
And the following applies to the supercession XKB000022 switch

Product Description

Up to VIN 5D345691 the brake light switch may have been coloured white for cars with cruise control fitted but this black switch is now suitable for those applications.

Brian
Thanks for that Brian. Unless I'm able to verify whether both elements of a double pole switch act in any way other than identically to each other, I conclude that my existing switch is doing its job on both outputs. In which case, it's a red herring.

I may need another T4 session.
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• Built 11/10/2004 @10:22 hrs
• 104,984/112,381
• 3,398/4,744
• 55/407 Ski Blue (JHI)

––––––––––––––––––––––––––––––––––––––––––––––––––
ZT 180+ Sports Auto
• Built 18/06/2002 @11:54 hrs: Registered 13/01/2003
• 4,906/18,894
• 206/813 Le Mans Green (HPD)
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Old 28th June 2020, 14:57   #9
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Quote:
Originally Posted by goltho View Post
Thanks for that Brian. Unless I'm able to verify whether both elements of a double pole switch act in any way other than identically to each other, I conclude that my existing switch is doing its job on both outputs. In which case, it's a red herring.

I may need another T4 session.
What colour switch is currently fitted? is it white or black?

The alternative is to buy a used switch from a breaker, originating from a KV6 auto fitted with cruise

Brian
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Sent from my Jupiter Ace running a 16k RAM pack and Chuck Moore FORTH

O ring failure guide HERE an invaluable guide to O ring failure modes, that don't include nonsense about positioning of clips on KV6 thermostat pipework

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Old 28th June 2020, 15:40   #10
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Quote:
Originally Posted by marinabrian View Post
What colour switch is currently fitted? is it white or black?

The alternative is to buy a used switch from a breaker, originating from a KV6 auto fitted with cruise

Brian
I've not managed to contort yet to see. But as it's talking to the EAT (and now the cruise relay) correctly, I've little reason to doubt it's faulty. So I'm currently stuffed.

Dougie.
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• Built 11/10/2004 @10:22 hrs
• 104,984/112,381
• 3,398/4,744
• 55/407 Ski Blue (JHI)

––––––––––––––––––––––––––––––––––––––––––––––––––
ZT 180+ Sports Auto
• Built 18/06/2002 @11:54 hrs: Registered 13/01/2003
• 4,906/18,894
• 206/813 Le Mans Green (HPD)
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