EDIT: 5/10/2017 - I hope to be reorganizing this thread or creating a new one soon so consolidate info. This thread was initially created as a Work in progress and turned into to goto reference. So, your answer is in here, but you may have to sift.
There have been tons of questions lately about cluster swaps. Since this was a final "todo" to complete my late interior swap into my '90, I decided to share my research and hopefully get some answers I still have. Hopefully, others will post up some fact on the swaps they did.
Some facts (some obvious):
1.) 89-90 G60 used Mechanical Speedometers
2.) 89-90 Clusters have a VSS (Vehicle Speed sensor) right off the back of the speedo (speedo Cable plugs into this). This is a Hall Effect sensor used for Cruise, Spoiler and MFI (Later called MFA)
3.) All 92- Clusters used a MAP sensor on the back of the cluster for Fuel Economy calcs. My Understanding (from the Bentley) is that these MAPs or at least what is referenced via the EEPROM is different between the G60 and SLC (Due to Boost and non Boost). This may just be a ref calc on the memory chip though and not the actual MAP sensor. For G60 you can set the MFA into Diagnostic mode and get vac/boost numbers right off the MFA display and can translate them into absolute pressures via the Bentley (I think most are well aware of this)
4.) All Corrados 91+ used digital speedos and a VSS off of the "Speedo drive unit in the transmission". This VSS can screw directly onto and early drive unit in place of the speedo cable if you are swapping to digital.
5.) 89-90 Clusters have most of the circuitry built into the gauges themselves. And there is no True "PCB" in the cluster per say.
6.) All Corrado Clusters use physically the same plugs in the Cluster (T28) and U1 and U2 that plug into the Fuse Box. Wire Positions will vary though. You should use the cluster pig tail from the cluster you are installing! If not, then you will have to verify pins via the table below.
7.) 89-90 had only one indicator light for Turn Signal courtesy. Later had 2 Arrows for left and right
8.) 89-90 has an overheat and Coolant light built into the Temp Gauge and later had the LED across the bottom with the others. There was a coolant control unit on the 90 that looks like a relay. If you are swapping from 90 to digital you will have to correct this (see post in below thread on how to jump this) or else you will be stuck with a blinking coolant light
Likely the Most Desirable:
1.) The 93+ cluster that has the red needles, refaced gauges and "Corrado" insignia on the Tach.
2.) 93+ clusters do not have a MAP and tie one wire into the ECU for an injector pulse signal to determine fuel economy. Change injectors or FPR and this will be inaccurate...
3.) Contrary to the Bentley and the early clusters, all of the wires from the cluster to the Fuse box in the late style are ALL WHITE WIRES (with the exception of 4)
4.) The Late Cluster (91+) uses a full PCB for it's circuitry and the gauges are in their rare form and just plug into the PCB.
5.) The oil Temp and External Temp senders are different than G60's (form wise)
All clusters have a wire for VSS out that drives the Spoiler Module, Cruise and MFA via Blue/White wires
Pin 1 = +12v (G1/4 i.e. Coil +12v)
Pin 2 = VSS Hall Signal (G1/11 -> U1/11 -> T28/27)
Pin 3 = Grnd (factory 91 = G1/6)
Now for the Good stuff
I successfully transplanted the later 93+ SLC Cluster into my 90. I had to get to the point where everythgin is functioning correctly, so the following posts describe my work in progress. Just note: there are errors that I have already found
Here is what happened initially after the swapt:
- Everything is in and works!! ...but needed to iron a few things
- The Tach Read low as I expected (going from a 6cyl to a 4). At about 900 I am ready about 600rpm. I may try to convert the signal and make it correct for the 4cyl via Megasquirt Tacho out or look at getting a later UK 16v tack with the higher redline. A Tach converter might work for others interested (momentum tuning, Dakota Digital or MSD).
EDIT: I ended up getting the PCB from a 91/92 Corrado and plugged in the later looking gauge modules. This gave me a correct tach reading and also has the Map sensor built in for the G60 MFA diagnostic and fuel eco calcs.
- i didn't have the Trans VSS from a 91-92 Corrado initially (and I am impatient), so I used the old Mech speed gauge only and soldered wires onto the VSS to drive the Late Speedo. The early gauge/VSS is driven via the cable obviously and is tucked out of site behind the late cluster. Works wonderfully
- There was no MFA Fuel Economy reading. The Violet/White wire that goes to the later ECU is an injector pulse.
- Outside Temp reads 122F when it should read ~80. Even though I tried both senders, both were bad. I used a new sender and this was corrected. Temp, I used and IAT sensor from and ABA as it had the same plug The reading was very close.
Here is the Wiring Cross Reference.
BE CAREFUL!!! If you follow the circuit diagrams in the Bentley, it shows that they swapped Pin 11 and 17 (Oil Temp Sender and + Term30) after '92. THIS IS WRONG and I think they mixed up the labels for T28/11 and T28/17 on the Cluster Diagram. I physically verified this is wrong and was the reason the Oil Temp was screwed.
-T28 is the 28 Prong plug in the back of the cluster
- U1 and U2 are the two blue plugs at the other end of the cluster pigtail that plugs into the Fuse box in said positions. i.e.: U1/2 would be Plug U1 and wire position #2, etc.
- Still need to verify the functions of wires T28/26 (to ECU) and T28/28
EDIT(s): Updated image to reflect Bentley being incorrect.
removed some of my posts to clean things up, since the questions and answers are shown in responses.
EDIT: 6/18/2008 Added pics.
Click for Larger Pics
'90 Cluster PCB
'91+ Cluster PCB (Coil Pack- late '93+ looks the same except it does not have the Map sensor on the back for the MFA. Late one is actually pictured below even though the gauges have earlier faces)
91+ Tach vs 90 style
My Temp Hack job soldering wires onto the 90 Speedo's Speed sensor to drive the Digital speedo. It does work , but I got the VSS now
91 Speedo vs Late 93+. Notice they appear interchangeable. Read threads below regarding this.
Modified by sdezego at 9:29 PM 6-18-2008