I've got a car in the garage right now that has the GNX dash cluster. All gauges are VDO. When you first hit the key, the needle on the speedo sweeps all the way to the right then sweeps back to 0, then never moves again. The vss is located by the powermaster with the stock cable going in one end and a grey wire coming out the side.........anyone know how to troubleshoot one ?
GNX dash cluster problem
- Thread starter Dwayne
- Start date
DJ Red Barron
Door-To-Door Pipelayer
- Joined
- May 10, 2003
Perhaps John at Casper's Electronics can assist.
847-247-0484
847-247-0484
1KWIKSIX
Well-Known Member
- Joined
- Sep 29, 2007
Electronic VDO Speedo Problem in GNX Dash Cluster
X2
Yup........John Spina would be your man.......
I've also got VDO gauges in my GNX Dash cluster....but my speedo is the older mechanical model.
Good luck chasing your gremlins....
Keep us posted in your progress....
dave
X2
Yup........John Spina would be your man.......
I've also got VDO gauges in my GNX Dash cluster....but my speedo is the older mechanical model.
Good luck chasing your gremlins....
Keep us posted in your progress....
dave
X3 for Caspers
Dwayne, I take it it's an electric speedo. Usually they will do the sweep thing when first powered up. If it never moves again I would say its not getting a signal from the sending unit OR it was never calibrated correctly. Was it just recently installed or is this something that just started happening.
Dave, how's the dash coming, when are you gonna send me some pics?
Matt
Dwayne, I take it it's an electric speedo. Usually they will do the sweep thing when first powered up. If it never moves again I would say its not getting a signal from the sending unit OR it was never calibrated correctly. Was it just recently installed or is this something that just started happening.
Dave, how's the dash coming, when are you gonna send me some pics?
Matt
........pulled the cluster. The first thing I see is these 2 wires balled up with electrical tape ( 1st pic).......the 2 wires in the gray sleeve come from pic #2, which I'm assuming is some sort of vss.......my question now is, if I drive down the road with a voltmeter attached to the wires from the vss, what will I see, if anything.........I would like to make sure I'm getting a signal from it before I move on to the next set.
Attachments
Dwayne,
Check this link out it may help.
http://usa.vdo.com/NR/rdonlyres/B77...0F10CC/0/HallEffectSensorWiringandTesting.pdf
Matt
Check this link out it may help.
http://usa.vdo.com/NR/rdonlyres/B77...0F10CC/0/HallEffectSensorWiringandTesting.pdf
Matt
Found it !..............I tested all electrical connections, took everything apart and soldered the connections and used shrink sleeve.........still nothing.....then I wised up and pulled the cable out of the side of tranny and low and behold, the drive cable was broke in half about an inch from the tranny......DUH !
harris48cars
Member
- Joined
- Nov 4, 2008
Just in case you removed the sending unit from the tranny and the drive pin fell out. It looks like it would work by installing either end, either way. Wrong. It is longer going in on one side or the other. Or it might have sheared off. Just something to check. I built four of the GNX dashs and all had the VDO electric speedo's. Never saw anyone else use the eletric speedo. Wonder if it's one of my old cars.
Gary
Gary
I didn't remove the sending unit from the tranny. Rebuilt the cable yesterday and re-installed.........still wouldn't work. Took the cable loose from the hall effect sensor and drove the car down the driveway and you could visually see the cable spinning......also tested the hall effect sensor and it cycled between 0 and 4.9 volts........I was sure it was fixed when I found the cable twisted in two !.........waiting on a TT chip at the moment, car will be back the middle of next week and I'm gonna pull the cluster again to go over it.........side note......on vdo's website, they say the hall effect sensor should cycle 0-4-0-4........I wonder if .9 volt has anything to do with it.
Dwayne,
Does mph show on scantool ? If so, how is the ECM getting it's signal?
In the photo of you holding the sending unit, where is the other end of the speedo cable ? ( the part that would go into factory speedo cluster )
Was there a little 2" X 1/16" square plastic piece in the sending unit?
I have a spare VDO "Vision Series" electric speedo somewhere in the garage that I can let you borrow to test and see if it's your speedo that took a dump.
PM if interested.
Matt
Does mph show on scantool ? If so, how is the ECM getting it's signal?
In the photo of you holding the sending unit, where is the other end of the speedo cable ? ( the part that would go into factory speedo cluster )
Was there a little 2" X 1/16" square plastic piece in the sending unit?
I have a spare VDO "Vision Series" electric speedo somewhere in the garage that I can let you borrow to test and see if it's your speedo that took a dump.
PM if interested.
Matt
I might take you up on that Matt.........the car is coming back in the next day or two......I'm gonna hook the directscan up to it and see if it shows mph going down the road.....the speedo cable goes from the tranny to the hall effect sensor then 2 wires from the sensor go to the gauge........the other half of the stock cable was lying in the trunk.
Dwayne,
If the ECM is showing MPH then it's getting it's signal from somewhere
Usually that is the cable from the tranny to the speedo head, but seeing as that is not connected it must be getting it from somewhere else. On my GNX dash conversion I used the same hall effect sender as yours to send signal to the ECM, but since my speedo is a mechanical one there is also a cable connected to the hall effect sender going to the back of my speedo.
I would trace that grey shielded wire ( with the two wires in it ) and see exactly where it goes.
When you measured the voltage was it at the wires at the back of the speedo? My thinking is if you got voltage there but speedo doesn't read then maybe those sending wires got shorted out and ruined the speedo internally. Gotta love the balled up electrical tape method for wiring.
Matt
If the ECM is showing MPH then it's getting it's signal from somewhere
Usually that is the cable from the tranny to the speedo head, but seeing as that is not connected it must be getting it from somewhere else. On my GNX dash conversion I used the same hall effect sender as yours to send signal to the ECM, but since my speedo is a mechanical one there is also a cable connected to the hall effect sender going to the back of my speedo.
I would trace that grey shielded wire ( with the two wires in it ) and see exactly where it goes.
When you measured the voltage was it at the wires at the back of the speedo? My thinking is if you got voltage there but speedo doesn't read then maybe those sending wires got shorted out and ruined the speedo internally. Gotta love the balled up electrical tape method for wiring.
Matt
Found the problem a couple of hours ago..........went driving around town with directscan hooked up and recorded some data. After watching the playback, the mph would just drop to 0 for a few frames and then return to normal. Back in the garage I started chasing that gray wire and found where it had been half-assed splice as it went thru the firewall........took it apart, soldered it up right.........put about 5 miles on it and it works fine.......Thanks again for the offer.
I seen you built four dashes. What are you using to take place of the VSS eye? Where do you get it? I got a VDO passthrough sender, but it puts out 16 pulses and the Buick ECU needs only 2.
Similar threads
