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Old 10-17-2019, 03:09 PM   #1
S70T5fivespeed
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Default Faulty gauges 91 740

I’ve seen bits and pieces of info on some recent threads here, as well as thru googles. Looking for current knowledge on the subject. Appreciate the help.

Have a 91 740 factory turbo with what seems like a failing cluster. First the gas gauge went limpy (like showing 10% on 90%) then just gave up, so I was using the trip odo for gas, but now Speedo has gone dead so no odo/trip odo or speed.

I know people say the 91/92 clusters are just bad, and I think others have said you can swap up to a better cluster (94/95 940?) so wondering what the best course is in this instance.

Also would the newer clusters match visually and feature a turbo gauge (I know these gauges are mostly useless but trying to keep this as oe as possible)

Otherwise is it possible to fix this one and perhaps make it stronger than original? Would be sending out to fix so not sure if costs on that would make it a poor choice.

Thanks
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Old 10-17-2019, 03:51 PM   #2
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First thing, take it out and reflow all the solder joints on the back. See where that gets you.

As far as 940 clusters go, they don't phisically fit, unless you swap the entire dashboard. Which is a straight fit, though it's going to take you a better part of a day, IF you know what you're doing.
Then it's onto pulling pins out of 740 plugs and into 940 plugs, since 740 and 940 clusters are wired differently. Plugs are great though, you don't neex any special tools to de/re-pin them, just both diagrams and go one wire at a time, because there are a couple of the same color...

As for making it stronger, what's the point? They lasted 25+ years before starting to fail, reflow gets them probably another 10, then some capacitors die, then you redo them and reflow it again, that's another 20-ish years. Are you going to drive it that long?
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Old 10-17-2019, 04:22 PM   #3
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Thanks Nord. That’s interesting you mention the 940 dash re: cluster. I thought the 940 dash was the same as the later 740 one, and have a replacement from a 940 I was planning to eventually put in.

As for driving this car ideally as long as possible.
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Old 10-17-2019, 08:50 PM   #4
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I had my 91 740T cluster repaired by DNA Speedometers, it worked perfectly after that. That's actually the second time I typed that tonight haha
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Old 10-17-2019, 09:02 PM   #5
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Thanks 2TT. Can I ask what something like that would cost?
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Old 10-17-2019, 09:24 PM   #6
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I believe it was about $300, I would have to find the receipt. This cluster used to be on their site with a price, it looks like the site has been redone and I couldn't find it easily. Their communication was very good however, and asking is always free haha.

https://dnaspeedometers.com/
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Old 10-17-2019, 09:31 PM   #7
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Yes thanks for the lead will def request a quote, no worries on hunting a receipt.

Thank you!
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Old 10-17-2019, 09:37 PM   #8
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No problem, I searched for a long time for a good used one, with no luck. I did read (while waiting for it to return to me) that since it is a 1 or 2 year only gauge the main difference was the gas gauge or something, most everything else is the same as a regular 740T gauge, but that was a very deep internet rabbit hole that I can't retrace.

It took a couple weeks to get it back, I drove around with my phone in the cluster hole with a GPS speedometer app during that time lol. Unfortunately I sold that cluster about 6 months ago, to a guy who was really bitter about paying me $200 or so for it.
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Old 10-17-2019, 10:08 PM   #9
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From what I’ve read about the 91/92 clusters figure better to fix than to swap anyway since most seem to fail.

But now I’m curious about this whole 7/9 dash fit issue, as I have a nice 9 dash I was hoping to put in my 91 740 with the oe 7 series trap cluster.
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Old 10-17-2019, 10:15 PM   #10
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Very true. I didn't regret fixing it. Good luck whichever path you take!
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Old 10-18-2019, 02:44 AM   #11
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I don't know, maybe US late model 740's god 940 dash from the factory?

Anyway, 740 cluster:



940 cluster:



There's the difference in size and shape, thus requiring corresponding dashboard.
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Old 10-18-2019, 02:59 AM   #12
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Originally Posted by nordmaschine View Post
I don't know, maybe US late model 740's god 940 dash from the factory?
Yup...




And 91 740 owner's manual:

https://volvornt.harte-hanks.com/man...740_01.htm#ch1
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Old 10-18-2019, 02:59 PM   #13
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Thanks MB that pic shows the one I’m working with (the 91-92)
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Old 10-18-2019, 05:56 PM   #14
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I have a 1990 760 Turbo cluster that... might work? And definitely could be yours. It's the trapezoidal style, with 120 mph speedo.
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Old 10-18-2019, 08:27 PM   #15
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Thanks RBP I think the clusters are pretty specific tho, 90 760 no workie with 91 740
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Old 10-18-2019, 09:00 PM   #16
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That's what I thought too. Oh well. I can take a picture of the circuit board if you want to play spot the difference but I think you're right.
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