How to install Abbott-ERA speedometer correction.

[work2muchplay2little]

OK, first things first. Thanks to Fest3er for putting me on the right track with the wiring. Second, the Abbott-ERA will only work correctly as it comes from the manufacturer (http://www.abbott-tach.com) for trucks with only Rear Wheel Anti-Lock Brakes (RWALB's). It has to be modified per Fest3er's instructions (on another thread) to work for All Wheel Anti-Lock Brakes (AWALB's) due to there being only a single speed sensor from the rear differential on RWALB's and both a single rear and left front and right front speed sensors on AWALB's.

Now for the installation. The Abbott box has four wires coming out of it: Red (12v ignition switched power) Black (chassis ground) White (in from speed sensor) Blue (out to Controller Anti-Lock Brakes [CAB]). The wires from the speed sensor coming into the CAB (an electronic box attached next to the brake master cylinder with a large multi-wire connector coming into it) are a white with violet tracer W/V and a red with violet tracer R/V. The Abbott manual indicates that the wire with the highest ohm reading (to ground) is the one to splice into. That is the red with violet tracer R/V and is (luckily) one of the wires on the top of the plug. Cut this wire and attach about a 4 foot piece of insulated, two conductor wire with the R/V wire coming from the speed sensor to the white wire of the Abbott box and the other end of the R/V going into the CAB to the blue wire of the Abbott box. I tapped fuse number 8 for power.

The directions supplied are pretty clear about how to calculate the correction ratio. In my case the stock tires went 681 revolutions per mile (you can find this info. at http://www.tirerack.com for most common tires) and the new ones (see sig) go 600 revolutions per mile. The ratio of 681/600 is 1. 135. Looking this up in the table supplied in the directions shows that the closest one is 1. 140, this is what I set the DIP switches to inside the box. I verified the correct MPH using a GPS unit and it is spot on.



Hope this is useful to others out there. Course, there goes my excuse... . yes sir officer, I just put these new tires on and my speedometer ain't right ... . FYI, Rickson is selling a new unit that works with AWALB's that doesn't need to be modified before use.

 

[work2muchplay2little]

Got one more "verification" of an accurate reading on my Abbott "enhanced" speedometer . State trooper clocked me at 75 mph (in a 70 mph zone) which is exactly what the speedo and the GPS indicated at the same time. BTW, no ticket and he liked the truck.

 

[csutton7]

thanks----chris

 

[fest3er]

There's one thing I would like to add. If you use crimp connectors, use the *smallest* one that will fit the wire. If you're short connectors, be sure you put a small one on the wire from the sensor. And it wouldn't hurt to solder this particular joint after crimping. The signal from the sensor is very small, and at low speeds, the Abbott box can 'lose' the signal, and stop sending a signal to the CAB.



On my truck, I had the drop-out problem for a long time until I got to diagnosing it. I replaced all the connectors with 22-18 (pink), and solved the problem. I *didn't* solder any of them, so soldering isn't really necessary, but is a good idea if you can do it.



Fest3er

 

[Kyle]

Question:

I'm getting ready to hook mine up (also a 99 4x4) and I have a question for you.



The instructions say splice the wires in "no more than 6 inches from the VSS. " That means I have to run the blue and white wires all the way back to the differential. Your instructions imply you spliced them in under the hood (right before the CAB). Is this what you did? If yours is working OK, I'll do the same and save myself a bunch of wire, split loom, and time.



Thanks for the help.



Kyle

 

[work2muchplay2little]

Yes, that's right - I spliced right before the CAB. It's still working fine after 4 months.

 

[Kyle]

Thanks

Thanks for the help. That's what I'll do too.

 

[michaelsgreene]

OK, so I have the Abbott box. I followed the instructions exactly, but with the box in line I have no speedo indication. I disconnected the in and out wires from the box and twisted them together and the speedo came back.



Is that red LED supposed to blink? Normally a blinking red LED is an error indication.



I even removed the crimp connectors and twisted the wires together for a run around the block, but no luck.



What about that other bank of DIP switches. It came set for the two-wire sensor, which appears to be what we have.



Michael

 

[michaelsgreene]

I did use the red/violet wire and when this wire is totally disconnected or run through the box there is no speedo.



Michael

 

[Kyle]

I went round and round with mine before I got it working.



There are some settings in that box that aren't "advertised". I don't remember them all -- my notes are at home.



I do remember that there's a switch to amplify the input from the VSS and another switch to amplify the output to the CAB.



I played with these as well as trying the "3-wire" setting.



Like I said, all my notes are at home so if you can wait til tomorrow, I can give you the specifics.



Otherwise, the folks at Abbott were VERY helpful. They faxed me instructions for my specific model, explained everything to me, told me how to run an internal test on the box, etc.



Let me know if you still need help. I'll check the board when I get home tonight and bring my notes in tomorrow if you don't get it worked out.



Good luck.

 

[michaelsgreene]

I e-mailed Abbott and they basically said, "try again. " The LED is supposed to blink.



I am very interested in your notes. I am leaving in the morning for a couple of weeks of delivering trailers, so it would be really nice to have it working. Otherwise, I have to fudge numbers to make the recordkeeping come out right.



I guess I could live with it a little longer.



Right now I am going out to solder all the connections.



Thanks in advance.



Michael

 

[Kyle]

I'll look for my notes tonight and post them here. It'll be late before I can get to it (after 9:00 PDT).



Just a note. I used "Weather Pack" plugs on all my connections. If the box goes bad, I can unplug it an send it in. I can unplug the splice into my VSS wire, plug the originals back together and it's factory again.



Originally we thought my connectors might be causing some signal loss so I connected about 6 of them together in line and couldn't measure any difference in resistance. (I did soldered all the wires to the connectors). The signal strength from the VSS is different in every truck because of proximity variations to the magnet in the sender. If your signal's weak, soldering might make a difference -- it didn't on my truck and soldering everything sure makes it tough to remove and reinstall later if necessary.



Just a thought... .....

 

[fest3er]

Originally posted by michaelsgreene
OK, so I have the Abbott box. I followed the instructions exactly, but with the box in line I have no speedo indication. I disconnected the in and out wires from the box and twisted them together and the speedo came back. ...

According to my '98 SM, there is no red/violet (RD/VT) wire.

It's been so long (65K miles) that my memory of the hookup is a bit fuzzy. However, the Abbott connects inline to the wire going to pin 1 (one; my '98 SM says this is RD/YL - red/yellow) of the CAB connector #1, with the white wire connecting to the sensor side, and the blue wire connecting to the connector side.

If Abbott had you connect it to pin 12, it won't work, unless Abbott have made changes to their design.

You *do* need a good, solid connection with the sensor. Its output is about 350mV at 1MPH or so; any resistance inline can cause the Abbott to see 'no signal' at slow speeds. I had this problem with mine for a while. I redid the connections (using more properly-sized crimp connectors) and have had no problems since.

Let me know if you still have problems.

Fest3er

 

[michaelsgreene]

The wires at the rear diff are red/violet and white/brown. It is interesting that the original post says that the red/violet is "right on top of the connector. " On mine it is halfway down the back side.



Breaking the red/violet does stop the speedo, so maybe I am on the wrong wire of the pair going to the sensor. Worth a try I guess.



Michael

 

[fest3er]

Originally posted by michaelsgreene
The wires at the rear diff are red/violet and white/brown. It is interesting that the original post says that the red/violet is "right on top of the connector. " On mine it is halfway down the back side.

Breaking the red/violet does stop the speedo, so maybe I am on the wrong wire of the pair going to the sensor. Worth a try I guess.

Michael

Those colors do not match the service manual. Oh well. For your '98 12V, you almost certainly want to splice into the wire going to pin #1. (Almost, because even though mine is a '98 12V 2500, who knows what DC might have done... . )

Turn the key off. Unplug the CAB connector #1 (the large one). Look at the plug. One of the pins should be 'blocked', or at least have no wire going to it. This will be pin #5, in a row of 7 pins. That will tell you which is pin #1. *That* is the wire you need to use.
The pins are numbered 1-7 in one row and 8-14 in t'other; pins 1 and 8 are adjacent.

Do *not* use pin #8 (next to pin #1, in the other row; pin #8 is grounded and won't work. Do *not* use pin 12; this is the wire going to the PCM. The Abbott will not work on this pin without modification. (See http://home.adelphia.net/~npmrphy/abbott-mod.pdf for info on the mod. )

Splice into pin #1 and it should work.

Fest3er

 

[michaelsgreene]

OK. I did as you said. On mine it is a wht/vio wire. Now I have a speedo indication, although I haven't checked it for accuracy against the GPS yet.



Funny that now it reads when backing up as well as when going forward.



Problem now is that the ABS light on the instrument panel stays on all the time. I tried disconnecting the batteries for a half hour to clear it and checked the fuse, but no luck. Guess I'll be buying a new ABS module.



Funny how the specific step by step instructions at the top of this post were exactly wrong. (At least for my application)



Thanks for you patient help. I'll let you know how the accuracy goes and maybe a miracle will happen and the ABS will cure itself.



Michael

 

[michaelsgreene]

Using your helpful description of the pin position, I have determined that I am on pin #8, which you indicate is incorrect. This is probably why the ABS light is on. The wire on pin #1 is red/yel, which doesn't match what is at the rear diff. The wire color must not be consistent.



I am confident that all will be well with one more wiring change and if all my women would just stop with the crisis after crisis mode, I might get it corrected and get back to work delivering trailers.



Thanks much again.



Michael

 

[work2muchplay2little]

Originally posted by michaelsgreene

Funny how the specific step by step instructions at the top of this post were exactly wrong. (At least for my application)Michael

Sorry to see that you had so much trouble with this project. I posted what worked for me based on my installation and what I learned from tracing out the wires and reviewing my service manual. I guess it just goes to show that DC can and does change things without notice. Hope you get the flawless performance from yours that I've enjoyed from mine.

 

[michaelsgreene]

Well, time for another idea. I very carefully located pine one, even found the pin numbers on the connector. Now the speedo sits at 15 mph while I am parked in the driveway and does not respond to vehicle motion at all. If I turn on the AC it goes up to 25 mph.



I crawled underneath the back end again with a flashlight and brake cleaner and the two wires going to the speed sensor are red/vio and wht/brn. These wires go to pins 8 and 4 respectively on the ABS module. 8 is open to ground and 4 is 1. 6 ohms. 8 is also the only one that has ever given a reasonable speedo indication, so I have to believe that is the right one. The only problem with that one is that the ABS light on the dash stays on.



Talked to Abbott again and they said send it back and we will refund your money. When I explained that that was not the optimum solution they said I should talk to Rickson and that they would e-mail some information.



BTW: I absolutely did not mean to criticize any of the advice offered. I am grateful for the help I have been patiently offered. I am just very frustrated by what should have been a simple project that seems to work for everybody else, just not for me.



Michael

 

[michaelsgreene]

OK. I feel stupid now. Somewhere in one of my trips around the block to test it out, I stepped on the ground lead and pulled it loose from the screw it was on. Anything after that didn't work. (imagine that) Pin #1 is correct, although I think that must go from the ABS box to the computer as it definitely does NOT go to the speed sensor.



Thanks for all the help and I will shut up and drive now.



Michael