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Username Post: Gauge cluster w/ tach        (Topic#344308)
bowtie44s 
Valued Contributor
Posts: 4283
bowtie44s
Age: 37
Loc: wv
Reg: 08-29-12
05-02-17 02:29 PM - Post#2689335    
    In response to socalarch

  • socalarch Said:
Is there a definitive way of telling the difference between the two?
Will a '91 cluster function in a '93 truck?



There is a picture of the back of an 88-91 here. https://www.chevytalk.org/fusionbb/showtopic.php?ti... If you have a 92-94 it won't look anything like that. I will say a 91 won't function in a 93. Anything is possible, but it would take major rewiring.

Jeff

'88 Chevy K3500, aluminum head roller cam 511in³ stroker 10.5:1 compression, 96 NV 4500, 94-98 grille, 305/70-16 (33x12) BF Goodrich KM2s, 91 cluster swap


 
socalarch 
Contributor
Posts: 167
socalarch
Loc: So. Bay L.A.
Reg: 09-13-10
05-02-17 03:04 PM - Post#2689341    
    In response to bowtie44s

Therefore, based on my photos posted earlier in this thread, my tach unit is an '92 or later.
What is the proper method of testing the white wire at the plug connector with a meter? With the truck running, what should the signal current measure?

I carved this cluster connector mounting point out of a '95 truck on my trip to the wrecking yard today. The intent is to rivet or glue this piece into place to the '88-'91 dash.

The additional parts plus the carpet for the back wall of the cab ran me a whopping $3.

Attachment: Photo0219.jpg (546.98 KB) 13 View(s)




Gary

1993 GMC Sierra 2500
1964 Buick Electra 225


Edited by socalarch on 05-02-17 03:08 PM. Reason for edit: No reason given.

 
rockfangd 
"7th Year" Gold Supporting Member
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rockfangd
Age: 34
Loc: Utica ny
Reg: 04-13-10
05-02-17 05:09 PM - Post#2689355    
    In response to socalarch

Simple answer is NO.
Not easily anyway.
I am going to go on a assumption here and say you bought the dash and the cluster out of 2 separate trucks. Am I right?
Please post a picture of the plug on your truck so it can be determined if it has a tach wire on it.
Also note that there is a v6 cluster and a v8 cluster. Will get into that more if you can get it at least functioning.
Also a 88-91 cluster plug is nothing like a 92-94, therefore I do not think you have a 91 cluster

Old School GM fan FOREVER


Edited by rockfangd on 05-02-17 05:13 PM. Reason for edit: No reason given.

 
CowboyTrukr 
"9th Year" Silver Supporting Member
Posts: 4385
CowboyTrukr
Loc: Salt Lake City
Reg: 06-20-09
05-02-17 05:24 PM - Post#2689357    
    In response to rockfangd

Here's his pic. It has the tach lead.



Attachment: med_1493588884-Photo0215.jpg (106.5 KB) 15 View(s)




Greg

'95 K1500 Z71 EC Short Step 5.7L+0.040/NV3500
'00 Explorer XLT 4.0 V6 Auto
'94 K2500 5.7 NV4500 ECLB - SOLD
‘87 GMC S15 SCLB 4.3 Auto - SOLD

"The only thing necessary for evil to triumph is for good men to do nothing" Sir Edmund Burke


 
socalarch 
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Posts: 167
socalarch
Loc: So. Bay L.A.
Reg: 09-13-10
05-02-17 06:51 PM - Post#2689368    
    In response to rockfangd

  • rockfangd Said:
Simple answer is NO.
Not easily anyway.
I am going to go on a assumption here and say you bought the dash and the cluster out of 2 separate trucks. Am I right? Yes, you are correct.
Please post a picture of the plug on your truck so it can be determined if it has a tach wire on it.
Also note that there is a v6 cluster and a v8 cluster. Will get into that more if you can get it at least functioning. Already posted above. The point is that there is a white wire in my existing cluster and the cluster I salvaged with the tach; they are identical. which is why it makes sense to me that there should be a current/signal coming across the white wire into the cluster and it should be detectable with an ohm meter. The question is what should that current be (millivolts, volts) and would one simply probe the red meter lead to the wire and put the black to ground?
Also a 88-91 cluster plug is nothing like a 92-94, therefore I do not think you have a 91 cluster. I think we are over the 88-91 cluster issue. Everything is 92-94.




Gary

1993 GMC Sierra 2500
1964 Buick Electra 225


Edited by socalarch on 05-02-17 06:55 PM. Reason for edit: No reason given.

 
rockfangd 
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Posts: 2870
rockfangd
Age: 34
Loc: Utica ny
Reg: 04-13-10
05-02-17 07:06 PM - Post#2689370    
    In response to socalarch

hmm.
The tach signal is a negative signal that is pulsed.
If it were me I would ohm the wire in the plug to the the spade under the hood. It should have 0 ohms.
I would recommend it with the battery disconnected.
Let me see if I can get the exact pin.
Edit. I think someone mentioned it was pin 7.
Look at the diagram I posted. Says it is Pin T. WHITE
Also look at the left side of the diagram as it mentions the splice I was referring to that joins the cluster feed, test spade, and coil feed together



Attachment: 94_cluster.pdf (68.56 KB) 24 View(s)

Old School GM fan FOREVER


Edited by rockfangd on 05-02-17 07:19 PM. Reason for edit: No reason given.

 
socalarch 
Contributor
Posts: 167
socalarch
Loc: So. Bay L.A.
Reg: 09-13-10
05-02-17 09:14 PM - Post#2689387    
    In response to rockfangd

  • rockfangd Said:
hmm.
The tach signal is a negative signal that is pulsed.
If it were me I would ohm the wire in the plug to the spade under the hood. It should have 0 ohms.
I would recommend it with the battery disconnected.This will show continuity, but is there a way to probe the white wire at the plug while the truck is running to confirm the pulse is being sent? With the plug not plugged into the cluster, positive probe to white wire, negative probe to ground, what would/should the pulse current be (millivolts, volts)? If the current is present at the wire but the tach does not move, then it would be an internal cluster issue of some sort- yes?
Let me see if I can get the exact pin.
Edit. I think someone mentioned it was pin 7.
Look at the diagram I posted. Says it is Pin T. WHITE
Also look at the left side of the diagram as it mentions the splice I was referring to that joins the cluster feed, test spade, and coil feed togetherReads just like the diagram I posted on 4/30.




Gary

1993 GMC Sierra 2500
1964 Buick Electra 225


 
someotherguy 
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someotherguy
Age: 49
Loc: Texas
Reg: 08-01-03
05-03-17 08:29 AM - Post#2689424    
    In response to socalarch

This one really went off the rails and I couldn't follow every response.

My best guess is an unlikely one historically, but makes most sense in this case. I think the tach cluster you got is probably defective. If you have the opportunity to try another, I would.

Richard

06 Silverado ISS / 06 Silverado SS / 06 300C SRT8


 
socalarch 
Contributor
Posts: 167
socalarch
Loc: So. Bay L.A.
Reg: 09-13-10
05-03-17 11:57 AM - Post#2689453    
    In response to someotherguy

Richard, maybe it's just your words of intimidation- the tach is functioning now (but the brake and information lights are on... I'll think about that later.
I have no clue as to why the first three times I plugged the unit in it wasn't working.

But I have answered some of my questions from above.
I followed ChevyTech's and Rockfangd's lead- I tested the white wire from the plug to connection C200 to the spade for continuity and resistance. All checked out fine.
I then followed my own query- started the truck and tested voltage from spade to ground- 11-12 volts. Then tested the white wire at the plug, T to Q/N on the connector- 11-12 volts.
Then plugged the unit in, started the truck and, voila.

Gary

1993 GMC Sierra 2500
1964 Buick Electra 225


 
rockfangd 
"7th Year" Gold Supporting Member
Posts: 2870
rockfangd
Age: 34
Loc: Utica ny
Reg: 04-13-10
05-03-17 06:10 PM - Post#2689498    
    In response to socalarch

cool.
It almost sounds like you are not getting a good connection to the plug at the cluster itself.
Did you try expanding the pins a little?
They press against the printed board, and if bent or worn slightly may not make good contact.

Old School GM fan FOREVER


 
Austmurr89 
Forum Newbie
Posts: 1

Reg: 09-18-17
09-18-17 08:49 AM - Post#2708005    
    In response to bowtie44s

You say u are familiar w the 88 to 90 moonie correct... I have an 89 and no speedometer reading I changed the sensor and nothing...



 
bowtie44s 
Valued Contributor
Posts: 4283
bowtie44s
Age: 37
Loc: wv
Reg: 08-29-12
09-18-17 04:28 PM - Post#2708050    
    In response to Austmurr89

It took me a while to figure it out but if you read this it will walk you through how to test it. https://www.chevytalk.org/fusionbb/showtopic.php?ti...

Jeff

'88 Chevy K3500, aluminum head roller cam 511in³ stroker 10.5:1 compression, 96 NV 4500, 94-98 grille, 305/70-16 (33x12) BF Goodrich KM2s, 91 cluster swap


 
B.eriic 
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Posts: 1

Reg: 01-31-20
02-01-20 12:00 AM - Post#2785583    
    In response to socalarch

Anybody know where I can buy this harness connector?



 
bowtie44s 
Valued Contributor
Posts: 4283
bowtie44s
Age: 37
Loc: wv
Reg: 08-29-12
02-01-20 10:18 PM - Post#2785656    
    In response to B.eriic

You won't find it new. You'll have to go to a junk yard.

Jeff

'88 Chevy K3500, aluminum head roller cam 511in³ stroker 10.5:1 compression, 96 NV 4500, 94-98 grille, 305/70-16 (33x12) BF Goodrich KM2s, 91 cluster swap


 
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