Early C-4 Instrument Cluster Interchangability?
Thread Starter
Pro
Joined: Jun 2003
Posts: 559
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From: OKC OK
Early C-4 Instrument Cluster Interchangability?
Okay...so...I'm finally getting to pay attention to the aesthetics of my '85 FrankenVette.
The dash is sunburnt and almost impossible to read. I'd sooner get one from ebay but have a question concerning interchangability.
What year units will directly interchange? Plug & play is what I'm after here! I'm not terribly concerned with bezel fit but with electronic compatibility. :seeya
[Modified by MtlSphere, 1:18 AM 10/21/2003]
The dash is sunburnt and almost impossible to read. I'd sooner get one from ebay but have a question concerning interchangability.
What year units will directly interchange? Plug & play is what I'm after here! I'm not terribly concerned with bezel fit but with electronic compatibility. :seeya
[Modified by MtlSphere, 1:18 AM 10/21/2003]
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
Re: Early C-4 Instrument Cluster Interchangability? (MtlSphere)
I'm assuming you're interested in digital gauges.
I tried trouble-shooting a friends 85 dash problems by plugging his 85 dash into my 86. Worked fine but idle below 1000 showed two digits instead of one. It showed 85 (meaning 850) instead of the single digit of 8. At 1000 RPMs and above it read normally.
Everything else worked fine in my car though. His problem is with his car not his dash.
I have a book downstairs somewhere that shows the different dashes that are out there. There is supposed to be a sticker on the back side of the dash identifying which one it is and they do change from year to year.
I can try to track the book down if you need that info.
A dark dash can sometimes be cause by a bad ground and there is a simple fix; soldering a ground wire on the circuit board. I'm trying to track down a photo that I use to have that shows exactly where to solder the wire.
Keep a check on the post I just put up on this thread to see if someone has the photo.
Let me know.
Jake
I tried trouble-shooting a friends 85 dash problems by plugging his 85 dash into my 86. Worked fine but idle below 1000 showed two digits instead of one. It showed 85 (meaning 850) instead of the single digit of 8. At 1000 RPMs and above it read normally.
Everything else worked fine in my car though. His problem is with his car not his dash.
I have a book downstairs somewhere that shows the different dashes that are out there. There is supposed to be a sticker on the back side of the dash identifying which one it is and they do change from year to year.
I can try to track the book down if you need that info.
A dark dash can sometimes be cause by a bad ground and there is a simple fix; soldering a ground wire on the circuit board. I'm trying to track down a photo that I use to have that shows exactly where to solder the wire.
Keep a check on the post I just put up on this thread to see if someone has the photo.
Let me know.
Jake
Melting Slicks
Joined: Jan 2003
Posts: 2,167
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From: What did the 5 fingers say to the face? SLAP!!
Re: Early C-4 Instrument Cluster Interchangability? (JAKE)
84 and 85 are interchangeable. They all plug in and work the same, but the 86-89 doesn't mount in the car correctly. I'm currently using an '85 dash in my '86 that I got off EBay. There are only 2 screws that line up in my car. My '85 dash MIGHT be for sale in the near future if I get around to getting my original dash fixed.
Melting Slicks
Joined: Jan 2003
Posts: 2,167
Likes: 0
From: What did the 5 fingers say to the face? SLAP!!
Re: Early C-4 Instrument Cluster Interchangability? (MtlSphere)
VERY IMPORTANT
If you do get a replacement cluster somewhere, make sure you check the code on the back of the unit. If your car has cruise control and the unit you put in comes from a car that didn't have it, your cruise will no longer work. It's amazing the amount of things that are controlled through that stupid dash cluster. Here are the codes to look for
LS 84/cruise
LT 84 w/o cruise
LAK 85w/cruise
LAL 85w/o cruise
LAW 86w/cruise
LAX 86w/o cruise
LBS 87-88w/cruise
LBT 87-88w/o cruise
LDL all 89
If you do get a replacement cluster somewhere, make sure you check the code on the back of the unit. If your car has cruise control and the unit you put in comes from a car that didn't have it, your cruise will no longer work. It's amazing the amount of things that are controlled through that stupid dash cluster. Here are the codes to look for
LS 84/cruise
LT 84 w/o cruise
LAK 85w/cruise
LAL 85w/o cruise
LAW 86w/cruise
LAX 86w/o cruise
LBS 87-88w/cruise
LBT 87-88w/o cruise
LDL all 89
Thread Starter
Pro
Joined: Jun 2003
Posts: 559
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From: OKC OK
Re: Early C-4 Instrument Cluster Interchangability? (flyersfan1088)
Thanks for the info! If your 85 dash comes up for sale please keep me in mind!! The car has cruise but I haven't been able to make it work. I knew the dash has the cruise processor. That's the other reason I'd like to replace the unit. I want my cruise to work!
Jake...the display is not dark but rather sunburnt (washed out) that's why it's so difficult to read. I know that I'm also having grounding issues because the display flickers and the voltmeter reads a consistent .5 volt low. I sure would like the name of that book you have though. SOunds like something I'd like to have for myself. :seeya
Jake...the display is not dark but rather sunburnt (washed out) that's why it's so difficult to read. I know that I'm also having grounding issues because the display flickers and the voltmeter reads a consistent .5 volt low. I sure would like the name of that book you have though. SOunds like something I'd like to have for myself. :seeya
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
Re: Early C-4 Instrument Cluster Interchangability? (MtlSphere)
I'm wondering if your washed out dash isn't just the result of the bulbs being burned out?
[Modified by JAKE, 12:50 PM 10/23/2003]
[Modified by JAKE, 12:50 PM 10/23/2003]
Thread Starter
Pro
Joined: Jun 2003
Posts: 559
Likes: 6
From: OKC OK
Re: Early C-4 Instrument Cluster Interchangability? (JAKE)
Well, I look slower than I really am...lol
The bulbs are all in working order. The displays have the classic washed out appearance. You can see the graph and number displays with the key off. They should be completely black. The numerical displays are almost completely washed out and very difficult to read. Now the tach display has started to deteriorate and that's the one I pay the most attention to anyway!
If I replace it with a dash from a 86 or later it should work but I'll have to replace the dash bezel as the angles are different. Kinda pricey at well over $100.00 but worth it I think. :seeya
The bulbs are all in working order. The displays have the classic washed out appearance. You can see the graph and number displays with the key off. They should be completely black. The numerical displays are almost completely washed out and very difficult to read. Now the tach display has started to deteriorate and that's the one I pay the most attention to anyway!
If I replace it with a dash from a 86 or later it should work but I'll have to replace the dash bezel as the angles are different. Kinda pricey at well over $100.00 but worth it I think. :seeya
Burning Brakes
Joined: Dec 2002
Posts: 1,088
Likes: 0
From: Lakeland fl
Re: Early C-4 Instrument Cluster Interchangability? (MtlSphere)
I bought an 84 cluster from EBAY toput in my 85. I got a good deal (?) because the seller stated that he didnt know if it worked and had no way to test it but he could state that the displays were not sunburnt and were not cracked. My 85 cluster illuminated but all three displays were cracked and did not function.
When I got the 84 home it didnt work when I plugged it in. So I took it apart and swapped circuit boards from the 85 to the 84 and BINGO- it works. But, the tach is different and seems a little screwy, all other guages work fine. I am satisfied with it because I was going to use an aftermarket tach anyway.
The moral to my story is that these parts are definately not all the same but may still be somewhat interchangeable with varying results. You take your chances I guess, and I got results that are acceptable to me. I paid like $140 for the 84, and for three undamaged displays I think I did allright. The best part to me is having a speedo and gas guage, all the other functions are just icing on the cake.
When I got the 84 home it didnt work when I plugged it in. So I took it apart and swapped circuit boards from the 85 to the 84 and BINGO- it works. But, the tach is different and seems a little screwy, all other guages work fine. I am satisfied with it because I was going to use an aftermarket tach anyway.
The moral to my story is that these parts are definately not all the same but may still be somewhat interchangeable with varying results. You take your chances I guess, and I got results that are acceptable to me. I paid like $140 for the 84, and for three undamaged displays I think I did allright. The best part to me is having a speedo and gas guage, all the other functions are just icing on the cake.
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Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
Re: Early C-4 Instrument Cluster Interchangability? (JAKE)
My friend bought a cluster off a wrecked 85 from a salvage yard for $50.00 and it worked fine in my car; but not his. His is a wiring problem in the car; not a cluster problem.
His battery contiunues to discharge when the car sits a few days and he hasn't solved the problem yet.
Jake
His battery contiunues to discharge when the car sits a few days and he hasn't solved the problem yet.
Jake
