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TD5 Connector Conundrum


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20150302_192601_zps445nitao.jpg

Evening all,

On my 2002 air con dash unit, I have an additional electrical plug from the wiring harness that I am unable to identify.

It's the natural coloured 3 way one in the picture above. 3 wires, a brown, a white and a white with a green trace.

I'm unable to find these wires in the Rave electrical circuit diagrams or the connector in the electrical libraries (have you any idea how fascinating trawling through a very, very long list of electrical connectors is ? It's not.) although it looks original and the harness wrap looks undisturbed.

Come on forum chums, what is it and where do the wires go ?

Mo

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You could always ping PaulMc a PM. He is the bible on harnesses/connectors.. :)

That one has me puzzled as well :unsure:

I looked for it, when Mo posted that picture a couple of days ago, here - http://forums.lr4x4.com/index.php?showtopic=93209&p=809302

The Discovery-2 uses that Sumitomo 250 series 3-way connector as one of the connections between the main harness and the heater harness - but, I've never seen it on the Defender - and, it doesn't appear in any of the Wiring Diagrams or Electrical Libraries that I have.

From the picture, it looks as though it's part of the A/C unit's harness, rather than the vehicle's harness.

The only connection between the A/C unit's harness and the vehicle's harness, is the Sumitomo Brown 7-way HD250 connector - I'm wondering if the 3-way connector is the A/C harness connection to the unit's blower motor?

.

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by Will Mcnab

Air Conditioning - 300Tdi

The air conditioning (A/C) system fitted to Defender operates independently of the standard heating and ventilation system. The A/C system is controlled by two rotary switches located on the driver side of the fascia; one switch controls blower speed, the other controls output temperature.

In order to gain maximum A/C system performance, the standard heater blower control should be set to '0', and both the temperature and distribution controls in the fully up position. The A/C system will then produce cooled and dehumidified air via the lower fascia vents.

NOTE: The A/C system will only operate when the engine is running.

Operation

Power Distribution

Feed from the positive battery terminal (C0192) is supplied to fusible link 1 and fusible link 5 of the under seat fuse box (C0632) on an N wire. Fusible link 1 is connected in series with fusible link 2, which is also located in the under seat fuse box. Fusible link 2 (C0570) provides a constant battery feed to fuse 28 and fuse 29 of the passenger compartment fuse box (C0595) on an NK wire.

Fuse 28 (C0595) provides a constant battery feed to the blower motor relay (C0153) on an NP then N wire. Fuse 29 (C0595) provides a constant battery feed to the compressor clutch relay (C1268) and the cooling fan relay (C0019) on a pair of NS wires.

Fusible link 5 of the under seat fuse box (C0570) provides a constant battery feed to the ignition switch (C1043 on LHD, C0028 on RHD) on an NW wire. When the ignition switch is turned to the 'ignition' position, current flows across the switch (C1732 on LHD, C0094 on RHD) to fuse 15 (C0580) of the passenger compartment fuse box on a W wire.

Fuse 15 (C0580) provides an ignition feed to the following on WG wires:

  • The blower motor relay (C0153)
  • The air conditioning unit (C1273)
  • The blower motor switch (C1508)
  • The air conditioning temperature control switch (C0275)
  • The compressor clutch relay (C1268)
  • The cooling fan relay (C0019).

Blower Motor

The blower motor relay coil (C0153) receives an ignition feed from fuse 15 of the passenger compartment fuse box (C0580) on a WG wire. The relay coil (C0153) is earthed on a UB then B wire. The energised blower motor relay (C0153) provides a feed to the blower motor (C0023) on a UW wire.

Blower Speed 1

When the rotary blower switch is in position 1, current flows across the blower motor windings (C0023) to the blower motor resistor (C0425) on a U wire. The blower motor resistor (C0425) is connected to the blower motor switch (C1508) by a G wire. As current has to flow through a high resistance rating within the blower motor resistor, the blower motor operates at slow speed. The blower motor switch (C1508) is earthed on a UB then B wire.

Blower Speed 2

When the rotary blower switch is in position 2, current flows across the blower motor windings (C0023) to the blower motor resistor (C0425) on a U wire. The blower motor resistor (C0425) is connected to the blower motor switch (C1508) by an NY wire. As current has to flow through a lower resistance rating within the blower motor resistor, the blower motor operates at increased speed. The blower motor switch (C1508) is earthed on a UB then B wire.

Blower Speed 3

When the rotary blower switch is in position 3, current flows across the blower motor windings (C0023) directly to the blower motor switch (C1508) on a U wire. As the blower motor resistor is by-passed, the blower motor operates at fast speed. The blower motor switch (C1508) is earthed on a UB then B wire.

Temperature Control

The temperature control switch relays operator input to the air conditioning unit, to control A/C system temperature output. The switch (C0275) receives an ignition feed from fuse 15 of the passenger compartment fuse box (C0580) on a WG wire.

When the switch is turned to position 1, a feed is provided to the air conditioning unit (C1273) on a UY wire. When the switch is turned to position 2, a feed is provided to the air conditioning unit (C1273) on a RW wire. When the switch is turned to position 3 (maximum cooling), a feed is provided to the air conditioning unit (C1273) on a B wire.

The switch (C1273) is earthed on a UB then B wire.

Evaporator Temperature Sensor

The evaporator temperature sensor is used to ensure the evaporator doesn't freeze. The air conditioning unit (C1273) provides a feed to the temperature sensor (C0134) on a K wire, and receives a return signal on a UW wire. The air conditioning unit (C1273) is earthed on a UB then B wire.

Compressor Clutch

When A/C is requested, the compressor clutch switch contacts (C0847) close. This allows current to flow from the compressor clutch relay coil (C1268) to the pressure sensor (C0279) on a WK then BS wire.

The air conditioning unit (C1273) provides a feed to the other side of the pressure sensor (C0279) on a UG wire. If the pressure within the high pressure side of the A/C system is within operational limits, the air conditioning unit removes its feed and replaces it with a path to earth. This has the effect of energising the compressor clutch relay.

The energised compressor clutch relay (C1268) provides a feed to the compressor clutch (C0182) on a BG wire. The clutch (C0182) is earthed on a B wire.

Condenser Fan

The cooling fan relay coil (C0019) receives a feed from fuse 15 of the passenger compartment fuse box (C0580) on a WG wire. The earth path for the relay coil (C0019) is controlled by the air conditioning fan switch (C0848) on a BP wire. If condenser cooling is required, the switch contacts close, creating a path to earth on a B wire.

The energised cooling fan relay (C0019) is now able to provide a feed to the condenser fan motor (C0280) on a BN wire. The motor (C0280) is earthed on a B wire.

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  • 3 months later...

I've just added the RAVE connector library for >02 Defenders, so the links will now work

p.s. It's my site and i'm in the process of moving across the data in a useful format so that the wiring diagrams can be more interactive. I hate having to switch between RAVE and the wiring diagram PDF, because RAVE is an old version of Adobe, it won't let you have both open at the same time!

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  • 1 month later...

To return to this chaps.

Having given much thought to this problem, do you think it could connect to the resistor pack ? Apparently these are located somewhere by the heater motor. Anyone know if this is so and have a picture of the resistor packs location ?

I eagerly await enlightenment ?

Mo

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Well, having opened the harness and followed the wires back down the loom, I now know their destination if not their purpose.

The white/green and the brown both tap into the harness, the brown into the blower supply using a crimped mechanical band wrapped in tape and the white/green to the main ignition switched junction also using a band.

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The last wire, the white one, goes to pin 6 on the air con control module. None of the wiring diagrams I can find show pin 6 being used. All the other wires are there as they should be.

It all looks original to me but to what purpose I have no idea ?

Anyone else got any ideas or theories ?

Mo

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Hmmm interesting bowie, except I don't think it has another air con controller and why would it need a 20 amp supply ?

My only thought is that is perhaps to control another air con unit, maybe in the back but that wouldn't be standard.

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  • 3 years later...

Hi! (Sorry for my English but I’m french)

I’m currently mounting an air con system from a Defender TD5 1999 to my 2006 one and I’m also very surprised by this 3 ways connector. Did I you finally find the use of this connector? I know it was 4 years ago but your answer could help me a lot!

thanx in advance.

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  • 1 year later...
On 7/14/2019 at 12:13 PM, Mo Murphy said:

Hallo Catalou66,

I never did find out but suspect it could be the connection for rear air con. 

Mo

Hi Mo, silly question but you didn't replace your ignition switch barrel prior to this failure? 

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