1997 Ford F350 - ABS Issue - FIXED

[Tim Martin]

Customer got this 97 F350 with diesel, auto trans, 4 by 4. The issue is that the amber ABS light comes on after turning on the ignition switch and doing its self check.

You can sit there with the engine running - light is on but as soon as the gearshift lever is placed in gear, the amber ABS light begins to flash a code 10 which is speed sensor. It has a new sensor and wiring harness on. I have ohms checked every circuit to the ABS Control Module behind the glovebox. I found continuity to ground on every circuit with the ABS module disconnected. Ain't that kind unusual? In checking the wiring under the truck and behind the dash, I am coming up dry.

What am I missing? It's midnight now and I am frustrated so I am hitting the sack so to speak.

[steven kiser]

the ground issue is more than likely a false reading because if nothing else the bulb. i see a blown fuse possibility. the kam fuse blown will cause this.

[Tim Martin]

I am inclined to agree with you on the ground issue. The FAP fuse was blown. I stuck a new one in but we still got the same issues. Might the control module be bad? Is there any way to test it?

[steven kiser]

in a nut shell, yes and no. i believe with the light flashing you'll be locked out of total diagnostics. if i were to be forced to guess i think you're going to find harness damage somewhere. i had a tow company that had a fleet of these and they at one time or another had a.b.s. issues. they ranged from wiring issues in the harness between the side tank and frame, where the harness ran up the l/f inner fender (the plastic skirt cut through the harness like a warm knife through butter), i even found that some "added" accessories were cut into the system. when i got stymied on one of these i would (with the agreement of the owner) unplug the module to completely shut down the a.b.s and get back into it at a later time. i would find a lot of my answers on iatn, direct hit, or google, now i also have the forum. when the shop is "open" and busy i can't dedicate the necessary time needed to investigate. for that matter even if i could force myself to i would go more batty than i am now because i know i could be doing something a lot more financially productive than spending hours on something that i will be in danger of loosing a customer if i charged for all the time i spend on it when i can only point to a wire that someone had back probed prior and didn't seal. it's funny, i can charge someone 2 grand for replacing a module and connector but if i charge someone 800 bucks for 10 hours diagnostic and repairing a short to ground because someone didn't clip in a harness they moved i'm a thief. again, sorry for the ramble.

[Tim Martin]

Nothing to be sorry about. Yer comments somewhat verified my suspicions that there may be wiring corrosion somewhere.

But I can concur with yer ideas bout charging for all the time we have in diagnostic time. Keep up the ramble. It becomes good reading material during coffee break.

[Tim Martin]

Have ya ever heard of the saying "He that persisteth winneth?" Well, I found the problem, exactly where steve proposed it mite be - the wiring behind the fuel tank in the frame rail. I run 2 new wires and lo and behold everythings working fine.