Volvo 850 upgrade to '98 x70 cluster...

[rspi]

Recently I have been dealing with several 850 cluster issues. From dead temp gauges, odo gears, dead fuel indicators, etc.

Anyway, some are turning to dropping the '98 clusters in the 850 since it's a perfect fit, no odo gear issue, some have the trip feature, etc. The problem is, that works great for the '96 and '97 850's but not the older ones. The speedo doesn't work. I looked at the plug harnesses of both and there are some differences. Does anyone here know what changes need to be made to get the '98 cluster to work in the older 850's?

[erikv11]

This topic has been beat to death over at Volvospeed, here's what I gather. Actually in many 95's the 98 cluster works just fine. Here's the catch: It must be late model 95 with OBDII, and it must be a Yazaki cluster. But as you said, for 96+ any 98 works. The 99 clusters are useless to the 850.

Early 95 and anything before that has the speedo problem, I have never heard of anyone getting it to work. jimmy57 has posted about it in some of your other threads rspi, he knows the details of why.

[rspi]

I'm a little lost at the Yazaki cluster comment. Are you saying that the 850 in late '95 has to have the Yazaki cluster? Some of the '94 850's have obd2.

My dash is getting pretty brittle so I'd hate to start toying with mine but I may with the other '95 car that has cluster issues.

[erikv11]

Sure, 94/95 whatever, OBD2 is the point there.

Maybe this is not so useful to you now that I think about your OP, but this is the way people do it: with a Yazaki cluster from a 94/95, you can swap over the gauges/faces from the x70 speedo into it, they are the same size/layout etc. So you get the x70 look and functional gauges. You keep the Yazaki cluster body because it can interpret the different speed signal in the 94/95, and talk to the x70 faces.

But if the 94/95 cluster body is somehow bad then this may not help you, sorry for the misdirection. I got distracted by the title and was posting more specifically about ways to upgrade clusters.

[rspi]

No problem. I do appreciate your input and thoughts.

[jimmy57]

Beats me how the 98 cluster would ever work in 95 down. The 95 down had not digital VS output to cluster so the cluster was wired direct to an analog VS sensor on the final drive housing of transaxle.
I investigated the possibility of the 98 cluster possibly having an analog input that was not used but existed. The same terminals used for analog input are used for other purposes on the 98 cluster. That doesn't mean the cluster doesn't possess that function but if it does it is on other unused/unlabeled pins.
Does the article on using the late cluster in the 95 mention any re-wiring?