I have done some searching about the ever popular sweep to ss conversion, and have actually done it a couple times, but i have been hired to chase the problems from a previous "mechanics" work. What i will be working on is a 71 chevelle that had a 72 dash and gauges installed with what i believe to be a 72 harness. i havnt got the car yet, but it is my understanding that none of the gauges work. The car does start and run, but no w/s wipers etc... after reading many of the threads on here i seem to have myself confused. The mose conclusive help i have found so far is the diagrams at www.azendrud.com/gauges/ can anyone clarify if that is exactly what i need or is there anything more in depth than swapping some pins in the fuse box bulkehead. thanks Levi

Elree had a nice post about which pins have to be switched, into what position, which pins to leave out because the 71 doesnt have the tcs. I just finished swapping all the pins on my 72 dash assy. and just about ready to install it, then I found another dash out of a 71 that hasnt been cut up for the radio hole or anything. Jim

The 71 and 72 harness are very different.

www.azendrud.com/gauges/ : The info here is for 70/71 only. (I know it says 70-72, but 72 is different)
72 underdash harness is very different at the bulkhead connector. I am surprised it started. Also the tach wire runs through the bulkhead connector on 72 only. The wiper switch is different for 72, it has an extra ground connection.

Elree info:
72 forward harness
If you look closely at the wire side of the dash harness bulkhead connector (separate the fuse block from the bulkhead connector) You should see letters marking the rows and columns. The rows are A,B,C and D. The columns are S,T,U and V for the forward lamp harness and W,X,Y and Z for the engine harness. The following instructions will refer to these coordinates.

Forward lamp harness
AS – No wire
BS – Tan wire (for brake warning light) -From DU
CS – Light Blue wire (for left hand direction signal) NO CHANGE
DS – Yellow wire (for windshield wiper power) -From CY
AT – Black wire (ground from steering wheel horn button for horn relay) -NO CHANGE
BT – Brown/white wire (from ignition switch to voltage regulator) -From CU. --Two wires on light harness. The second, Brown is from the GEN light.
CT – Dark Blue wire (for right hand direction signal) NO CHANGE
DT – Light Blue wire (for windshield wiper) -From DY
AU – Light Green wire (for headlights high beam) NO CHANGE
BU – Brown wire (for running lights) -From BU
CU – Dark blue wire (for windshield wiper) -From CZ
DU – Black wire (for windshield wiper) -From DZ
AV – Tan wire (for headlight low beam) NO CHANGE
DV – No wire

Engine harness
AW – No wire (engine harness has black wire to trans switch for TCS)
DW – Red wire (main power feed from horn relay/starter) -From DV
AX – No wire (Would be a tan wire for TCS)
BX – Pink wire (connects to a brown or white/orange/ppl resistance wire to coil +) NO CHANGE
CX – Black/White wire (for amp gauge) -From DT --No wire on light dash harness
DX – Black wire (for amp gauge) -From DS--No wire on light dash harness.
AY – Brown wire (for tachometer to coil -) --No wire on light dash harness. On the 71 gauge dash harness this wire passes through the firewall.
BY – Dark Blue wire (for oil pressure switch) NO CHANGE
CY – No wire
DY – No wire
AZ – Purple wire (to starter solenoid) -From AW
BZ – Orange wire (for heater blower not used on air conditioned car) NO CHANGE
CZ – Dark Green wire (for engine water temp sender) -From BS --Temp switch on light harness.
DZ – No wire (would be dark blue for TCS
solenoid)

So the wiring listed above is correct for a 72 harness going into a 71, or is it just how the 72 harness is originally? I have to do my wiring soon. I'm doing a swap with 72 Monte harness (dummy lights) into 72 Malibu sweep. I got a kit with the guages to wire only themselves with jumper wires, but will the rest be a direct plug-in at the bulkhead?

The previous information is for modifying a 70/71 harness for use in a 72.

The following is for a 72 harness for use on a 70/71.

If you look closely at the wire side of the dash harness bulkhead connector (separate the fuse block from the bulkhead connector) You should see letters marking the rows and columns. The rows are A,B,C and D. The columns are S,T,U and V for the forward lamp harness and W,X,Y and Z for the engine harness. The following instructions will refer to these coordinates.

FORWARD LAMP HARNESS BULK HEAD CONNECTOR
AS – No wire (Should be black wire for key warning buzzer. Your warning buzzer will be under the dash,)
BS – Dark Green – temp sensor for temp gauge or temp switch for temp light – Move from CZ
CS –No change (Light Blue –LH dir signal)
DS –Black – J-block /amp gauge –Move from DX Forward lamp harness wire to be added. Gauge cluster harness only
AT –No change (Black grounds at horn button for horn relay)
BT –No wire
CT –No change (Dark Blue –RH dir signal)
DT –Black/dark Blue/White (looks like Black/White) –horn relay / amp gauge –Move from CX. Forward lamp harness wire to be added. Gauge cluster harness only.
AU –No change (Light Green -head light high beams)
BU –No change (Brown –running/marker lights)
CU –Brown/White –voltage regulator / ignition switch (The brown white wire from the ignition switch is a resistor wire, supplies power to the voltage regulator when key is on) -brown wire to GEN light (light harness only) –Move from BT.
DU –Tan –brake dist block / brake warning light –Move from BS
AV –No change (Tan –head light low beams)
DV –Red –Main power feed to dash –Move from WD

ENGINE HARNESS BULKHEAD CONNECTOR
AW –Purple –starter solenoid S terminal / Neutral safety switch –Move from AZ
DW –No wire
AX –No wire (would be TCS)
BX –No change (Pink to ignition switch / engine side has white/orange /purple to coil)
CX –No wire
DX –No wire
AY –No Change (brown –coil / tach) Engine side wire to be added. Gauge cluster only.
BY –No Change (dark blue oil pressure switch / oil warning light)
CY –Yellow –power to wiper motor / wiper fuse –Move from DS
DY –Light Blue –wiper motor (washer pump) / wiper switch –Move from DT
AZ –No wire
BZ –No change (orange blower motor / blower switch) Used on heat only cars, not used on A/C cars.
CZ –Dark Blue –wiper motor / wiper switch –Move from CU
DZ –Black –wiper motor / wiper switch –Move from DU

Note: The wire in AY is found in a gauge dash harness only it is for the tach to coil. For a 70/71 harness this wire is not routed through the bulkhead connector. It is routed through a hole in the firewall.
Wires in DS and DT are for the AMP gauge, also gauge harness only wires. You will need to add these wires from the cluster connector to the connections under the hood.

Now, what if I wanted the space shuttle dash instead???

Thanks for the good info.