The electric tape idea sounds good...but I wouldn't be able to sleep at night. Where is the brake presssure switch located and what am I checking for? Continuity or ohms? Thanks for the tip, Pete

 

check the switch on the master cyl.... also check your fluid level.

if your brakes make your cruise turn off then the brake switch is ok.

i think thats how that works..... but i do not know for sure

kenny

 

Thanks, I found the pressure switch and checked the continuity and the switch is good. (Closed when brake is off, Open when brake is depressed. Someone had mentioned that air is in the system. How it checks for that I cant say. But I will bleed the system and see if that works. All my speed sensors are cleaned and working. I let you know what I find

 

how do you know all the sensors are working?

they are reluctance sensors, if you wave a piece of metal in front of them it should produce a voltage across the 2 pins that crosses 0V

btw, to clear the abs light you have to drive over 30 i think

kenny

 

Kenny, Well I'm assuming their good by what Barney674 stated about the ohs being 1.9k ohm or higher. I read infinity on all my sensors and the speedo is working so I guess the sensors must be good. How do you read the voltage across the sensor with the sensor pluged in? do you pierce the insulation on the wires with your meter leads?

 

the sensor can be tested without being plugged in.

Beleive it or not my front sensors read 750 ohm, when not plugged in... you may want to check that. If the sensor is detected as open, it will definitly throw a light

you can check the voltage by unplugging the sensor and read ac volts (i like to use a fluke 87 multimeter cause it gives freq too) you can have somebody move the truck back and forth a little bit... if there is no voltage change then its a bad 1. tone ring, 2. sensor

kenny

 

All my sensors read open and I tried reading millivolts and fanning a scew driver across the sensor but read nothing. I will repeat this with a fluke 87 and see if that makes a difference. I cant believe all my sensors are open and not working. The differential sensor is for the speedo I believe and my speedo is working). But maybe it can also get its information from the turbo sensor off the tranny. I still haven't checked that one. I'll let you know. This is a terrific web site BTW.

 

what year model is truck?

kenny

 

Kenny, It's a 2000 F150 2WD, 4.2 V-6. But what a difference a meter makes. I used a Fluke 73 this time and guess what?...I read continuity on my two front wheel sensors, but infinity on the differential sensor. Replaced the bad sensor and all is well again. But is an interesting thing I discovered. Even though the coil was open I could get my meter to pulse a voltage by fanning the screw driver across it. The magnetic field distorted by the screw driver induces a votage across the meter. You know the collapsing and expanding of the magentic field...basic electricity. So simply put (you were right about an open circuit) must have continuity first..then do the voltage check if needed.
Thanks, Pete

 

i am very glad you found it... I was thinking it was a superduty truck and never asked... i should have asked first.

the 150's have a turbine shaft sensor that has to match the rear VSS i think. that was your problem i guess


kenny

 

Here is my story from beginning thru resolution:<?xml:namespace prefix = o ns = "urn:schemas-microsoft-comfficeffice" /><o></o>
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Problem: My truck (1999 F350 7.3L diesel, 4x4, SRW, CC, LB, with 116,400 miles) has been running great with no problems until I started it this morning (going to take some Boy Scout on a bicycle trip). I had not even made it out of my neighborhood when I noticed that the ABS light was on, the speedometer was not working, and the TCIL (overdrive light on the end of the gear shift lever) was blinking / flashing. Needless to say I felt pretty sick that 3 major problems had suddenly appeared overnight. Since the truck was running and shifting smoothly, and continued to run and shift smoothly, I completed the day trip and returned home having driven approx 45 miles without incident. The odometer only registered about 7 miles driven. I had parked it and restarted it at various times during the trip, hopefully wishing the problems would go away as mysteriously as they had appeared, but they never did. The odometer had worked very briefly and sporadically, but never registered an accurate speed as far as I could tell. I never tried using the cruise, so not sure if it may have been effected as well.<o></o>
<o> </o>
Troubleshooting: My troubleshooting was done on the internet, mostly on this great site. With 3 problems to research, I had a lot of searching and reading to do. By reading between the lines and combining some of the lesson learned in various threads and posts, it seemed obvious that all three problems were related to a dirty or faulty VSS (speed sensor located on the top of my differential). The first thing I tried was removing it and cleaning it. A short test drive thru the neighborhood quickly showed that it had not worked, nothing had changed. So, I removed it a second time with the intent of replacing it and noticed that it was just as dirty and gunked up as before. This time when I cleaned it, I also cleaned out the hole, replaced it, and took another test drive – no change!<o></o>
<o> </o>
Resolution: Simply stated, I went to Auto Zone, paid $18.99 (plus tax) for a new VSS, installed it, took a short test drive thru the neighborhood and, thankfully, all the problems were gone, like they had never existed in the first place!!! I have not been out on major roads yet, but hopefully this was all there was to my problem!!<o></o>
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i have a 2001 f550 with 7.3L speedo is erratic and abs light is on checked fuses all are good changed speed sensor on trans and vss on diff no effect cruise works until speedo goes erratic