MK4 Clocks -> CE2 wiring

Hallo there! This was recently asked for on the book of face, and its much easier for me to put a post up for it rather than try to explain on there! Anyway here goes, its a little bit of a work in progress as my mate changed his mind about his MK4 dash swap so I never got to finish the clock loom 100%

T32 (blue)
1 - blk/pur - ignition live - U1/4
2 - blk/grn - right indicator - *3 pin plug
3 - blu/wht - VSS output - U2/2
5 - pur/blk - fuel gauge - U1/12
7 - brn/wht - common sensor earth U2/13
8 - pur - coolant temp gauge - U2/9
9 - brn - earth - U1/10
10 - grn/blk - oil pressure switch - U1/3
11 - grn/brn - rev counter - U1/6
12 - blu - alternator - u2/12
17 - wht - main beam warning - U2/7
18 - blk/wht - left indicator - *3 pin plug
20 - gry/blu - dash illumination - U1/14
22 - pur/red - coolant level warning - U2/5
23 - red/pur - live feed - u2/11
24 - brn - earth - U1/10
25 - gry/wht - VAG-COM port
28 - grn - speedo sender pin 2 - U1/11

Separate flylead pins:
14 - gry/wht - rear fog warning
16 - tailgate open warning
21 - brn/yel - door contact switch (lights on/door open warning)
26 - gry/red - right sidelights on (lights on warning)
27 - gry/blk - left sidelights on (lights on warning)
30 - yel/red - ignition switch pin SU (lights on warning)

Unused MK4 wires: (which you may want to use?)
4 - trailer tow warning
6 - airbag
13 - backrest lock warning
15 - n/a
19 - ABS
29 - blu/brn - brake fluid warning light
31 - seatbelt warning
32 - n/a

***************************************************************
T32a (green)
2 - grn - key reader pin 1
5 - gry/wht - diagnostics from ECU - U1/9
6 - pur/wht - washer fluid level warning - U1/7
13 - brn/yel - handbrake warning switch - U2/10
17 - blk - key reader pin 2
18 - brn/blu - oil level/temp sender pin 3 - U1/1
19 - org/blk - CAN-HIGH, to ECU- U1/8 (only needed if using later MK4 can-bus type ECU)
20 - org/brn - CAN-LOW, to ECU - U1/5 (only needed if using later MK4 can-bus type ECU)
26 - brn/yel - MFA outside temp sensor - U1/2
27 - org/blk - vagcom port pin 6 (CAN-HIGH)
28 - org/brn - vagcom port pin 14 (CAN-LOW)
32 - grn/wht - MPG signal - *3 pin plug

Separate flylead pins:
3 - sidelight warning
23 - blu - MFA stalk pin 2 (top button, display switches down)
24 - blu/grn - MFA stalk pin 1 (bottom button, display switches up)
25 - blu/gry - MFA stalk pin 4 (reset)

1 - n/a
4 - data CAN bus input screen
7 - gry/grn - front left brake pad wear sensor
8 - external buzzer (lights on?)
\- CAN-HIGH, internal convenience for connection to CCM & Radio (01 onwards)
9 - External gong (e.g. for seat belt warning system)
\- CAN-LOW, internal convenience for connection to CCM & Radio (01 onwards)
10 - Fuel reserve warning (only certain countries)
11 - vehicle stationary (early climatronic only)
12 - a/c shut off (temp signal for climatronic?)
14 - ASR/ESP warning
15 - Fault warning lamp for electric accelerator mechanism
16 - Immobilizer, relay output
22 - brn/red - bonnet switch
21 - Signal for oil temperature warning (vehicles without oil level warning)
29 - data CAN bus output screen
30 - Output signal 2 from electronic speedometer (clock, navi units)
31 - Selector lever position display (data, navi units)
32 - Fuel consumption signal (enable, navi units)

Used spares and their output pins:
U1/5 - G2/11 (low oil pressure)
U1/7 - G1/2 (outside temp sensor)
U1/8 - G2/5 (glow plug)
U1/9 - G1/9 (check light)

Unused CE2 pins:
U1/13 - R/1
U2/1 - E/2
U2/3 - D/10

Notes:
The 3 pin plug I mention is a MK3 Golf thing, this is where the indicator and mpg wirign comes in on the later ECU looms. On early MK3 looms there is a 2 and 1 pin plug for this (engine and lighting looms split)

The flylead pins mentioned above you will have to wire outside of the fusebox, those to use or not are up to you. for example the sidelight, door pin and ignition pins are only needed if you want the lights on and/or door open warnings to work. Factory the sidelight pins would be tapped into the rear wiring loom, door pin on a mk3 goes to a handy jumper box above the fusebox so you could do this too. Key in ignition SU wire to ignition switch will need some kind of plug. The sides & indicators could all be taken from the stalk looms if you prefer, this could reduce the amout of random plugs you have, possibly a single 4 pin for indicators and sides taken off the indicator/parking light plugs perhaps.

U/1, 7, 8 and 9 have been cunningly re-purposed from their original mk2 functions to reduce wire joins between the clock and other car looms. For example T32a/5 -> U1/9, then on the ecu loom you put the grey/white diagnostics wire to G1/9.

G2/11 was originally for the low oil pressure switch, and since there is only 1 oil switch on a MK4 you can repurpose this pin. For outside air temp sensor G1/2 goes thru the fusebox into the clock loom, then is joined back to the main clock earth on the clock blue ribbon foil so you can re-purpose that as well. You can then tap the outside temp sensor to earth in the engine loom somewhere, or move it to G1/6 which is earthed inside the fusebox.

If you want the immobiliser to work you can actually splice the MK4 key reader wires to a MK3 reader coil, I have tested this and it works This is the pinout I used, but it probably doesnt matter which way round you wire it:
black -> brown
green -> white

Any more questions and clarifications please ask, as I say this thread is a work in progress and will probably evolve into a full MK4 -> CE2 thread. I might possibly cover CE1 too but this fusebox has far fewer internal feeds so it would involve a hell of a lot more flyleads, so in my book if you're going to the trouble of a MK4 swap you may as well do a CE2 loom swap at the same time!

 

mk3 mpg wire is the purple/white hanging out of the clock plug, either on its own or in a 3 pin plug wit hthe indicator wirign dependign on the age of the car it came from. the rev counter is can-bus on later MK4 but the signal is still there on later ecu as it is required by the climatronic control module regardless of the age of the car

 

I've heard vague things about it from various sources, the problem is the mk4 sender works in reverse to mk1-3 senders so you either need to mod a mk4 unit in or 'flip' the mk1-3 sender so it works opposite. something about swapping wires on it were mentioned but I cant help more than that? hopefully someone will chime in

 

aye sender feed and an earth

 

aye if you have a MK3 tank thats probably the easiest way to go about it, or graft the mk4 level sender to the mk3 upper part