speedometer not working

[edram454]

I had a post earlier about the src (service suspension light) and light would not go off. I was working on my car and I had turned it on and off a few times so the src light came on. Of course all we have to do is drive it a few feet and the light goes off. In my case it would go off and come on again. I didnt realize that the speedometer for some reason stopped marking miles per hour and miles.

the speedo is on and still measuring gas consumption but anything related to marking miles is just at zero. I guess this is the reason why the src light will not go off. the car thinks it is not moving so the light cant clear. I grounded the a-c on the aldl and it listed all the codes, 12,13,etc...up to 43. I think when the light on the src is not cleared it sees the whole system as needing service not just one component. so now the question, what would cause the speedo not to mark miles. This is a rebuilt gauge cluster and it shines bright and marks gasoline usage etc... just not moving miles, no odometer, no mph,, . I tried disconnecting battery hoping it would clear the problem but it did not.

I was told the speedo gets is information via the transmission sensor. I hear it is a yellow and green wire that goes in to the drivers side of the transmission and that is where it gets its speedometer mph information. Have any of you had this issue??

ed ramos #3028

[WVZR-1]

Does it display the miles and the trip information but just not record increases OR there is no display at all? Is this a new fault since installing the rebuilt cluster? Has it worked at all since the cluster install?

VSS is yellow and purple wires.

[edram454]

no miles on trip odometer or miles on the odometer. The display is zero. the odometer miles don't move either the speedmeter.. it just stays at zero. It displays the current mileage at 45505 but just stays there. The cluster worked beautifully up until a couple of days ago but I just realized it yesterday since I drove on the turnpike and noticed the mph was standing at zero. it measures gasoline usage but no trip odometer mileage, no mph and oven computerized averaged miles per gallon will not work since it is not measuring forward movement of any kind. this is a very recent occurrence since I removed my spare tire and spare tire holder and did some cleaning under the car. I will be checking that sensor on the drivers side of tranny. this was a beautifully looking and working cluster prior to this problem. It was rebuilt and the lights are bright etc..

[edram454]

Originally Posted by edram454

no miles on trip odometer or miles on the odometer. The display is zero. the odometer miles don't move either the speedmeter.. it just stays at zero. It displays the current mileage at 45505 but just stays there. The cluster worked beautifully up until a couple of days ago but I just realized it yesterday since I drove on the turnpike and noticed the mph was standing at zero. it measures gasoline usage but no trip odometer mileage, no mph and oven computerized averaged miles per gallon will not work since it is not measuring forward movement of any kind. this is a very recent occurrence since I removed my spare tire and spare tire holder and did some cleaning under the car. I will be checking that sensor on the drivers side of tranny. this was a beautifully looking and working cluster prior to this problem. It was rebuilt and the lights are bright etc..

Yes you are right. yellow and purple wires. this is bizarre.

[WVZR-1]

If it displays miles and has since the cluster you should check the connection at the VSS first and it seems likely the fault.

If the connector is good at the VSS the FSM diagnostics are next. Don't just buy a VSS, it requires a specific one.

[edram454]

thanks. I will do just that. I need to get it on my race ramps and take a look. Maybe even the wires have somehow touched the header pipes or something. Unfortunately I wont be able to do this until the weekend. Thanks for your input.

ed ramos #3028

[PhillipsLT5]

check the sensor, mine gave out after the 181.3 mph pass

[scottfab]

Originally Posted by edram454

... snip...
I was told the speedo gets is information via the transmission sensor. I hear it is a yellow and green wire that goes in to the drivers side of the transmission and that is where it gets its speedometer mph information. Have any of you had this issue??

ed ramos #3028

This is from a past email on the list server:
"The VSS signal goes directly to the Selective Ride Control system and then to the ECM where it gets turned into a square wave for the rest of the car. If you don't have a SRC #23 error the VSS might be good and the problem could be with the ECM or a wiring problem. The new pn for the '90 VSS sensor is 25007224."

I hope it's the VSS connector. It could be lots of fun finding one of these.

[edram454]

Originally Posted by scottfab

This is from a past email on the list server:
"The VSS signal goes directly to the Selective Ride Control system and then to the ECM where it gets turned into a square wave for the rest of the car. If you don't have a SRC #23 error the VSS might be good and the problem could be with the ECM or a wiring problem. The new pn for the '90 VSS sensor is 25007224."

I hope it's the VSS connector. It could be lots of fun finding one of these.

I grounded both the a-c pins on the aldl and it blinked every code in the src. I believe once the src comes on after three starts and no movement, the car needs to move in order to turn off the src light. If the speedo is not marking any miles or movement the src light will not go off and if you do a diagnostic during this situation you will see that it throws all codes for the src. There is nothing wrong with the suspension it is the speedo that is not letting the light turn off since the car thinks it is not moving. Once I fix the speedo and the car thinks it has moved the light will clear out like always. I just dont know it is the vss sensor or a loose wire etc..?? I will have to find out.

ed ramos #3028

[WVZR-1]

I've never done it because I've always had the "correct" parts but I believe the later VSS will work in the '90 only requiring the connector being changed at the VSS. I've exchanged a couple emails with a fellow that he thought so but I never received a follow-up regarding that.

Yours would be maybe an interesting conversation if the wiring and the connector are in good shape. There would be a couple different procedures that you could use to accomplish the connection. Cut/splice, cut and use correct terminals and shell or construct a pig-tail adapter from one to the other. I understand the terminals and they could be purchased locally separately and the pig-tail adapter would be 3" long.

The correct VSS for a '90 has been obsolete for a long while. I have an NOS correct one but only one.