Where is the ABS valve power relay located on 2004 Mercury Sable ? ABS light on and code C1266 showing.

Question edited for clarity.
Question moved to model category.

Relay 4 in the engine compartment fuse box.

Mercury Sable (2000-2005) fuses and relays

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2000, 2001, 2002, 2003 - The fuse box is located below and to the left of the steering wheel by the brake pedal. The location of the fuses in the passenger ...

When on, this means the anti lock brake system is not functioning. The brakes will work however in a panic stop situation the ab a system will not function and the car will not stop as quickly. A code scanner that can read abs codes is needed to determine what the failure is.

run the fault codes to see where the faulty sensor is

C0110 is abs pump circut problem. The pump is located on the frame rail under drivers seat area. The abs pump comes on to apply brakes as needed for the stability and abs systems. There is a fuse as well as a relay in the relay-fuse center under the hood on the drivers side. please check the fuse and switch the relay with another one that looks the same.

need to take it in and diagnose

that click would be the relay check for power at the horn itself

they can go bad-swap it out with another that you don't need, just to try and see if it is the relay-listed are relays that might only control, for instance, the rear window defroster-generally, relays are all the same, some just get used heavily and some don't (i.e., ABS)-worth a try

Horns are usually located at the front of the vehicle next to or below the radiator. Check the wiring and horn relay. Also have a look at the fuses.

The fuse block is usually located on the left side under dash or behind a small cover on that side. If the fuses are ok change the signal relay, after that the signal/light switch on the steering column.

ABS light on problems are either the result of bad wheel sensors, bad connectors, or bad ABS relay.

The relay is usually mounted to the top of the ABS module (it was on my '01 Tahoe). And until mine went out, I didn't know these things were problematic. I found a place in Moscow, IA that rebuilds them for $150 and gives a 5 year warranty. You pull your off, send it to them, and have it back in less that a week.

Find their website by Googling ABS repair, Moscow, IA. They have a troubleshooting guide and everything on their website.