[V8] Instrument cluster repaired (long!)

pdlord at talent.com.au pdlord at talent.com.au
Thu Jun 16 01:54:42 EDT 2005

So there I was starting to think my V8 was just getting too hard for me to fix, 
with more 'issues' with it than when I started out fixing it. My hobby car was 
becoming very frustrating. Now I've finally made some headway.

The Instrument Cluster is a not a good set-up, esp. on RHD cars (apparently 
it's similar in design as the US 200tq) as you have to twist the cluster out of 
the dash, and no matter how careful you are, the whole assembly flexes slightly 
on the opening as you pull it out. Not a good start, as I discovered later.

I took out the cluster to fix an inoperative temp gauge and strange dash 
backlighting (common prob, as on 200tq, instrument back lighting includes 
indicators and high beam light and you lose some speedo backlighting at the 
same time). I tried the 'clean all connections' route, then not really knowing 
what I was looking at, put it all back. Then I lost oil temp, pressure and 
voltmeter as well! Then the speedo died as well(which will also affect trip 
computer readings and servotronic light does not extinguish). At about the same 
time, the car was starting really rough. I was not a happy camper...

Both the speedo and backlighting issues were fixed by resoldering the 2 
connections on the main board, where the pins from the back of the speedo 
insert into. On the reverse side of my RHD V8's board, these are green plastic 
covered connections. I also bent slightly the speedo pins so as to ensure a 
better connection, which also means you have to watch carefully as you re-
assemble the board, so as not to bend and break these pins - use a small 
screwdriver to guide them in. 

I first thought I had it fixed several times - the lazy way - by just bending 
these green connector points but it wasn't enough to fix the problem, perhaps 
because the solder had cracked on the connections, at a guess. The best I got 
was an intermittant operation of dash lights. Not the result I was looking for. 

The voltmeter and oil temp/press gauges not working was because of a tear in 
the main board for (I think) these gauges' common earth circuit. There is an 
exposed part of the board on the bottom edge when it's all assembled, and this 
is what can rub on the dash as you pull out the cluster. That's what happened 
to mine - it was already slightly buckled and weakened at that pooint anyhow, 
and pulling it out also introduced a tear at that point. I soldered a bridging 
wire across the tear and the gauges work again. I discovered this was the 
problem by bridging what I thought was an insignificant tear with a small 

Much of my frustrations came from not being a very good soldering iron 
operator - my new fandangled gas soldering iron was parked and I pulled out my 
old AC powered iron I last used when I was a kid. The gas one was either 
too 'cold' or too hot to successfully heat the board, wire and solder so it 
would all stick. I lost count of the bridging wires that simply fell off the 
board, or the insulation I melted. Eventually I was able to control better the 
temperature with my old iron and all was sweet.

Put it all together and everything works, except the temp gauge, which is 
probably a sender unit problem. 

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