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Old Dec 31, 2013 | 10:24 AM
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Spedometer

So I put a radio in my truck (78 250) it all went well so I decided I was gonna try to fix my cluster lights. I tried to take out the insturment panel, and it fell apart as that plastic tends to do. Everything worked, spedometer, gauges, etc.
I got a new cluster, hooked it all up and the spedometer will not work. Doesnt move a bit. But when I got it I turned the deal on the back and the spedometer worked. I have it all hooked up the way it was before, any ideas of what im missing.
 
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Old Dec 31, 2013 | 10:37 AM
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Sounds like your speedo cable isn't seated fully, or it's cracked. Try a replacement cable.

Also, I don't know if it was coincidence, but my truck had a 100mph gauge in it, and the needle bounced all over the place, I found an 85mph gauge, and it works great. there might be a difference in the driven gears.
 
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Old Dec 31, 2013 | 10:57 AM
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Agreed, sounds like it's not seated all the way. It should click into place.

Don't you love how simple projects turn into big headaches?
 
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Old Dec 31, 2013 | 11:08 AM
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Yes carefully double ck it for being seated by pulling straight out on the white lock clip. And if it feels good there, pop it out the trans and give it a spin ck from that end.
 
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Old Jan 2, 2014 | 05:35 PM
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Originally Posted by fmc400
Agreed, sounds like it's not seated all the way. It should click into place.

Don't you love how simple projects turn into big headaches?
Thank you everybody for the replys, well I wanted to avoid it but I took out the cluster,then took the cable off the speedometer and jacked the back wheels off the ground and started the truck. Put it in gear and the white (the square peice that makes the speedometer spin) doesnt move. I dont know what I did to the speedo cable but now its broken. Hope that makes since, I was gonna check the gear in the transmission next.
And yes FMC, I think im the only one it happens too, the simplest jobs where everything should fit right in turns into a hassle
 
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Old Jan 2, 2014 | 06:50 PM
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I think im the only one it happens too, the simplest jobs where everything should fit right in turns into a hassle
Definitely not. I fight many of the same little battles everytime i want to fix something. It teaches you preparedness. I broke a speedo cable on my jeep when i removed the gauge, I would say that being in there for about 40 years made it brittle, and when you pulled the old gauges out, it broke. its really to be expected. On the plus side a new cable is only $20 or so.
 
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Old Jan 5, 2014 | 06:57 PM
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Originally Posted by Ordnance
Definitely not. I fight many of the same little battles everytime i want to fix something. It teaches you preparedness. I broke a speedo cable on my jeep when i removed the gauge, I would say that being in there for about 40 years made it brittle, and when you pulled the old gauges out, it broke. its really to be expected. On the plus side a new cable is only $20 or so.
Turns out it was broken right before the sensor for the cruise control. (Its a metal deal with wires coming out so I think its for the cruise control lol) Thanks
 
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Old Jan 5, 2014 | 08:20 PM
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What is it?

What IS that metal thing with the wires? I'm working on tracing my my speedo cable back to find the problem and I have made it to this thing. My truck doesn't have cruise..so what is it?

Nick
 
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Old Jan 6, 2014 | 07:54 AM
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Originally Posted by 79SPRCAB
What IS that metal thing with the wires?
You're going to have to be a lot more specific than "metal thing with wires." Try posting a picture.
 
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Old Jan 6, 2014 | 04:41 PM
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Flying saucer

It's aluminum and about 2 1/2" in diameter and shaped like a flying saucer. The speedo cable has a junction on either side maybe 18" down the cable from the instrument cluster. It has 2 wires that come out of it.

Nick
 
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Old Jan 11, 2014 | 03:09 PM
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I realize this was terribly unspecific, but how many "metal things with wires" are there on the speedo cable?
 
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Old Jan 11, 2014 | 03:17 PM
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I bet it was a speedo cable that had the provisions for cruise control ? Just not used??
 
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Old Jan 11, 2014 | 03:51 PM
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Originally Posted by 79SPRCAB
I realize this was terribly unspecific, but how many "metal things with wires" are there on the speedo cable?
How am I supposed to answer that question until I know what you're talking about in the first place?

The item you've described is called a variable reluctance sensor and serves as the speed input to the cruise control amplifier.
 
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Old Jan 15, 2014 | 05:12 PM
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Good to know thanks!
 
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