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I have a 2008 F150. I’m thinking it’s the rear differential abs sensor everything looked okay on it however my abs light comes on after I start the truck. After a few minutes of the truck being started and warming up the abs light comes on without moving at all now I checked rear harness looked good I checked the sensor itself with the truck off sensor unplugged I tested the two prongs for resistance and my ohm meter just stayed at 1. Didn’t change a bit leading me to believe it’s the rear sensor , anyone know how to test rear sensor properly to make sure I’m doing this right I put it on 2k and got nothing , also no brake warning lights coming on and speedometer works fine so I’m thinking this is the culprit just wanna be sure. If I’m driving and the light comes on usually upon first time I hit the brakes it might kick abs on for a second or two then go away and no more abs pushback from the pedal after that.
On another note as well:
the rear brake lines have what looks like a rear differential vent tube connected to them and it runs up to the truck bed now this vent line is ripped off right at the bracket where it meets the brake lines and the axle tube, think this will cause me any problems ?
When you turn the key ON -- but not START, you see the ABS light.... When you START the truck, the light goes out momentarily.. Computer check continuity thru the sensors as you set in one place.. Light comes back on if the front or rear sensors are open circuit... If no light, then you put in gear and move... Computer checks that each sensor has OUTPUT.. If no output, the light comes on as you reach 5- 10 mph..
Apparently your FIRST check for continuity is BAD and light comes on.. Can be sensor or bad wire... Have you worked on front wheels / hubs , and move the wire / speed pickup ?? Look for damage... front and rear.
Actually Steve's info reminded me when I got my '07 I had the ABS light. My Autel AL619 said left front WSS.
I happened upon a WSS for $7 delivered from China on Amazon. Figured WTH and ordered it. It looked EXACTLY like the OEM when I removed the old one. It's been in for ~4 years now with zero problems. They're hovering around $70 at O'Reilly (for 4wd), but to be fair you're paying an "insurance premium" for their LT warranty
When you turn the key ON -- but not START, you see the ABS light.... When you START the truck, the light goes out momentarily.. Computer check continuity thru the sensors as you set in one place.. Light comes back on if the front or rear sensors are open circuit... If no light, then you put in gear and move... Computer checks that each sensor has OUTPUT.. If no output, the light comes on as you reach 5- 10 mph..
Apparently your FIRST check for continuity is BAD and light comes on.. Can be sensor or bad wire... Have you worked on front wheels / hubs , and move the wire / speed pickup ?? Look for damage... front and rear.
yeah I haven’t done any work to the truck just got it a few months ago think imma scan it so it can tell me which sensor it is cause I checked the wiring and connections and all look good , it comes on every time I start the truck after a few seconds of idling. Sometimes after a few minutes it comes on but it’s usually pretty quick. And that’s without me moving at all it comes on. On the rare occasion the abs light doesn’t come on after starting it by the time I reach the end of my driveway it will come on and abs brakes will kick back a little but then never again after that when I’m driving. Also it just started sounding like I have a wheel bearing going bad as of today so I planned on doing the front hubs soon. Prolly will get the ones with new abs wires and sensors and then replace the rear sensor too at the same time.
For a long time my parking brake light has come on intermittently, and now stays on most of the time. More recently the odometer back light won't come on most of the time. Now the ABS light has started coming on intermittently. None are FULL time on, and no rhyme or reason, as all actual items are working fine otherwise.
I'm pretty sure these are all faulty/cracked solder lines on the instrument cluster circuit board. There are places that can repair these instrument clusters, but it's still too cold out for me to pull and send off my cluster.
For a long time my parking brake light has come on intermittently, and now stays on most of the time. More recently the odometer back light won't come on most of the time. Now the ABS light has started coming on intermittently. None are FULL time on, and no rhyme or reason, as all actual items are working fine otherwise.
I'm pretty sure these are all faulty/cracked solder lines on the instrument cluster circuit board. There are places that can repair these instrument clusters, but it's still too cold out for me to pull and send off my cluster.
Ya know I've not heard of the ABS light being part of the cluster stupidity, but that doesn't mean it can't be I suppose. The brake light is textbook as is the LCD backlight.
The airbag light can also do dumb stuff, it's never worked on my '07 from when I purchased at 185k to now at 220k. I just swapped to an XLT cluster and airbag light is fixed LOL. This meant for the first time in my ownership I could turn off the seatbelt nanny chime the right way (instead of a seat belt extender to fool it)
I just had the wife's '08 cluster repaired by Texas Speedo in Arlington. $89. Recommend. They list on ebay
