Alfa Romeo Forums banner
1 - 17 of 17 Posts

·
Registered
Joined
·
228 Posts
Discussion Starter · #1 ·
I am looking at a good series 3 instrument cluster to possibly replace a bad series 4 instrument pod. Does anybody know if these are interchangeable?
 

·
Registered
Joined
·
837 Posts
Where would you put the auxiliary gauges?
 

·
Premium Member
Joined
·
3,863 Posts
I am looking at a good series 3 instrument cluster to possibly replace a bad series 4 instrument pod. Does anybody know if these are interchangeable?
I don't think so.

I have a S4 and have an S3 pod spare (bought it when I had an S3). When I plugged the S3 into my S4 and the Speedometer wouldn't work.

Vin
 

·
Registered
Joined
·
228 Posts
Discussion Starter · #5 ·
The S 4 is a 91. Both The Tach & speedo are kupt. The speedo sending unit is sending the impulse to the speedo and the tach is all over the place. Could the wiring of the S3 pod be reversed from the S4?
 

·
Registered
Joined
·
9,741 Posts
check the speedo first: this is electronic, so check fuse 7 first (same fuse as the blower heater, so if that is working the fuse is OK) - does both the speedo and mileometer not work? If so it points to the sender (under the car mounted on a chassis member near the exhaust), the fuse (7) or the cable (short version). If the speedo doesn't work but the mileometer/tripmeter DOES work then indeed it is the speedo itself.
alfa spider S4 speedometer - Alfa Romeo Forum
 

·
Registered
Joined
·
1,350 Posts
I bought an S3 pod to repair bits to the S4. They are not just "plug and play" as you have found, but you can take bits out and swap.

For example, the top parts, with the oil pressure gauge and voltmeter are identical. So you can separate this easily from the rest and change over.

The wiring on the lower part is a bit different but in essence the same - there is a power feed and a ground take off which serves all the instruments and lights. Then there is a feed for the speedo, for the tacho, for the temp gauge etc. and you should be able to trace these just by looking at the circuit board. Its not as complex as it looks.
You could then cut and swap wires going into the plug that fits on to the circuit board accordingly.
I have swapped the speedo from the S3 pod into an S4 and it works fine. Once you have taken the internals of the pod out, undo the four screws at the back, behind the speedo, and it lifts out from the front. The electrical connectors are four push fit pins.
I couldn't swap the tacho easily as on the S3 pod I have it fixes in with bolts and nuts which also make the electrical connections (like the fuel gauge and other gauges) whereas the S4 is a push fit onto the electrical connectors then held in by screws like the speedo.

I've got the S3 pod partially dismantled so can post some photos if that would be helpful.

If the tacho is working but inaccurate then it is likely that the potentiometer (variable resistor) which calibrates it is in need of replacement. SS4s link to the Speedo thread will be helpful but I will get a photo to show the one I mean. If you can solder you can replace it yourself for about $1.
 

·
Registered
Joined
·
1,350 Posts
some pics

The attached pics show the four connectors that attach to the rear of the instrument pod, one to the top section and the others to the lower.
Note that on an intact pod there will be corresponding colour plastic fittings which hold these in place on the circuit board. A tab on the plug locates into this plastic fitting, make sure you push this back with the tip of a screwdriver before pulling the plugs off. I have taken these fittings from the pod to replace broken ones on my other pod.
The others are views of the back of the pod showing circuit board (a flexible film), and the two sections separated.
 

Attachments

·
Registered
Joined
·
1,350 Posts
tacho pics

The tacho, showing possibly faulty potentiometer. As per the thread that SS4 highlighted, you can spray this with contact cleaner and turn the screw back and forth a few times to get it working again but that is short term. If you have got this far its worth replacing it.
Undo the two screws from the front of tacho and pull the needle off the centre spindle then you have access to the board. Measure the resistance across the potentiometer with the screw turned fully one way then the other to give you the range. Then buy a modern equivalent from an electronics store and replace. This particular one is showing about 200 ohms and I believe it works so this would mean getting a new pot. with a range of perhaps 0 - 250ohms.
 

Attachments

·
Registered
Alfa Romeo Spider 2.0, Alfa Romeo 166 3.0
Joined
·
163 Posts
km and trippmeter not working

Friends, I have the opposite problem, my speedo and tachmeter work fine but both the km (distance) and tripmeter both stopped working after i reset the tripmeter during driving quickly away from a gasstation in the latest Mille Miglia. Is this a mechanical fault?
 

·
Registered
Joined
·
9,741 Posts
Friends, I have the opposite problem, my speedo and tachmeter work fine but both the km (distance) and tripmeter both stopped working after i reset the tripmeter during driving quickly away from a gasstation in the latest Mille Miglia. Is this a mechanical fault?
Probably mechanical: from what I gather there is a separate little motor that turns the odometer/mileometer cogs, so could be you broke a cog tooth by resetting it whilst driving.
(odometer should only be reset at a standstill)

but also possibly electrical: the odometer motor is powered by 2 'chips' on the circuitboard (On the german forum these chips were called IC's and numbered SAF 1090 and SAF 1091)
(but these are no longer available, afaik. Well, at least back in 2008 they weren't!)
 

·
Registered
Joined
·
554 Posts
if you Speedo is working but your odo is stationary, the most likely cause is a small [nylonish] 25tooth gear that drives the odo. It becomes "mushy-gummy" over the years and the teeth disentigrate. It is available from specialists like Palo Alto for some $$. There is also a stepper motor that drives the odo but they rarely fail.
 

·
Registered
Alfa Romeo Spider 2.0, Alfa Romeo 166 3.0
Joined
·
163 Posts
Palo Alto

Thanks for your answers.
SpiderHolly, do you have any contact to this Palo Alto? Tried to Google but got to many hits that seemed irrelevant.
 

·
Registered
Joined
·
833 Posts
power seat belt speedo cluster 1988

I am looking at a good series 3 instrument cluster to possibly replace a bad series 4 instrument pod. Does anybody know if these are interchangeable?
the power seat belt speedo cluster off an 1988 spider( veloce or quad) will work on 1991 to 1994 (s4)spider,
not easy to find a power seat belt speedo cluster off 1988 spider(s3) very rare,
all gauges work,the wiring is different on this type of speedo pod,




i
 
1 - 17 of 17 Posts
Top