H
High Tech Redneck
Guest
1992 Ford Aerostar Van Speedometer Problem
This would normally be an easy fix (I thought). The digital Speedometer is reading zero (0) regardless of the forward speed, which also stopped the cruise control from working, and it no longer shifts into the Overdrive gear. All was working fine until just a few weeks ago.
Normally this would be replacing just the Speed Sensor. This model does not have one in the transmission, but does have one in the rear differential gear box. This was a first for me not normally being familiar with Ford’s, but after some searching for the right part, and matching it up at the Ford Dealer by hand, this van has an 89 model rear end (Complete with junk yard part number). The dealer matched the part number with a Ford OEM Replacement. But, I still have the same problem.
This vehicle does not have a speedometer cable I can find on the A4LD automatic transmission, it does have one five pin connector I can’t identify on the center driver’s side above the linkage shift and passing gear cables, and a two pin sensor in above the pan and filter (I’d guess for low transmission fluid level warning light?).
I’ve been through all the under dash fuses, none are blown. I haven’t pulled the dash out to check the electronics yet, for which I don’t have the schematics or wiring diagrams to that amount of detail. It does apparently have a fuel computer that calculates the gallons remaining in numbers and bar graph, average mileage, trip counter and odometer, low fuel warning, etc. All of these functions seem to have problems without the speedometer working. Experience tells me one item failing can cause many issues, but I’m wondering where the electronics that control the digital gauges on the dash could be located. In case I’m chasing the wrong end of the problem.
The Ford parts dealer mentioned there is a Ring Gear the speed sensor lines up with in the differential. I’m wondering how to check it. I do on occasion at low speed hear a “Rattle” in the back, but can’t tell if it is in the transmission or the rear end. I would say it sounds like a broken speedometer cable, except if this van has one, I haven’t found it yet underneath. Thus the plans to remove the dash assy and instruments later to see if a cable is connected or not to the speedometer, and I just haven’t found it yet.
This is an ongoing problem for the last few weeks, but no one beyond the speed sensor in the rear end, seems to know what may be causing the problem.
Normally I wouldn’t worry about it, but cruise control is nice to have, and overdrive gear for better gas mileage, and keeping my speed in check in my GA small town full of speed traps and deputies that outweigh me.
Real answers would be helpful.
This would normally be an easy fix (I thought). The digital Speedometer is reading zero (0) regardless of the forward speed, which also stopped the cruise control from working, and it no longer shifts into the Overdrive gear. All was working fine until just a few weeks ago.
Normally this would be replacing just the Speed Sensor. This model does not have one in the transmission, but does have one in the rear differential gear box. This was a first for me not normally being familiar with Ford’s, but after some searching for the right part, and matching it up at the Ford Dealer by hand, this van has an 89 model rear end (Complete with junk yard part number). The dealer matched the part number with a Ford OEM Replacement. But, I still have the same problem.
This vehicle does not have a speedometer cable I can find on the A4LD automatic transmission, it does have one five pin connector I can’t identify on the center driver’s side above the linkage shift and passing gear cables, and a two pin sensor in above the pan and filter (I’d guess for low transmission fluid level warning light?).
I’ve been through all the under dash fuses, none are blown. I haven’t pulled the dash out to check the electronics yet, for which I don’t have the schematics or wiring diagrams to that amount of detail. It does apparently have a fuel computer that calculates the gallons remaining in numbers and bar graph, average mileage, trip counter and odometer, low fuel warning, etc. All of these functions seem to have problems without the speedometer working. Experience tells me one item failing can cause many issues, but I’m wondering where the electronics that control the digital gauges on the dash could be located. In case I’m chasing the wrong end of the problem.
The Ford parts dealer mentioned there is a Ring Gear the speed sensor lines up with in the differential. I’m wondering how to check it. I do on occasion at low speed hear a “Rattle” in the back, but can’t tell if it is in the transmission or the rear end. I would say it sounds like a broken speedometer cable, except if this van has one, I haven’t found it yet underneath. Thus the plans to remove the dash assy and instruments later to see if a cable is connected or not to the speedometer, and I just haven’t found it yet.
This is an ongoing problem for the last few weeks, but no one beyond the speed sensor in the rear end, seems to know what may be causing the problem.
Normally I wouldn’t worry about it, but cruise control is nice to have, and overdrive gear for better gas mileage, and keeping my speed in check in my GA small town full of speed traps and deputies that outweigh me.
Real answers would be helpful.