ABS light

[94ford]

recently i powerwashed the engine compartment and now the abs light comes on every so often. i replaced the sensor and it is still occuring. there are no disconnected wires that i can see under the hood. if anyone can help it would be greatly appreciated,

thanks

 

[94ford]

anyone???

 

[Hawk1339]

All wheel ABS?

 

[94ford]

no rear wheel only

 

[multiranger]

no rear wheel only

there are 2 ground wires on the neg battery cable.. one goes to the ecm the other the ABS module.. Check there...

 

[Hawk1339]

There's not much relating to RABS under the hood that could have been disturbed by power washing. Check the master cylinder float switch- if it's not working it will turn on the ABS light. Check the ABS resistor/diode, on a 94 they should be plugged into the power distribution box under the hood.

I've had an issue with the float switch connector- dirty contacts causing a random ABS light.

When all else fails you can get the fault code from the RABS computer. See this procedure:

RABS_diag.pdf

Not sure about a 94, but on my 93 the diag connector is directly forward of the parking brake pedal, clamped to the big round multiwire connector that comes through the firewall.

 

[94ford]

I've had an issue with the float switch connector- dirty contacts causing a random ABS light.
well the light doesnt permanentaly stay on if it was the float switch connector wouldnt it always be on

 

[Hawk1339]

well the light doesnt permanentaly stay on if it was the float switch connector wouldnt it always be on

The issue I had was an intermittent ABS light. Sometimes the problem would clear and the ABS computer would cancel the fault. At first, the brake warning light would come on simultaneously, dimmer than with the parking brake. That is how it should work, the float switch sends a signal to the ABS computer and turns on the brake warning light through a diode. Eventually the brake warning light stopped coming on but the ABS light was still intermittent. I replaced the diode and the pull up resistor but it still wasn't right. I then took the switch off of the reservoir and tested it, it worked fine. The contacts on the switch were heavily oxidized so I cleaned them, and the problem went away.

You can test the lights this way: Ignition on, engine not running, parking brake off. Disconnect the connector from the float switch. Take a short piece of wire and connect the black wire to the green/yellow wire. That should turn on the brake warning light. Connect the black wire to the tan/light green wire. That should turn on the ABS light. If you have the RABS diagnostic procedure (linked above), you can run that and should have a fault code 12. Clear the fault as outlined in the procedure.

You should run the diagnostic procedure in any case, that will tell you where to start looking.

 

[94ford]

i took the connector off the master cylinder and the light continues to stay on. have any ideas on what else it can be?

 

[Hawk1339]

i took the connector off the master cylinder and the light continues to stay on. have any ideas on what else it can be?

Run the diagnostic and post the results. Any other approach is just voodoo.

http://users.isp.com/vmstep/stuff/RABS_diag.pdf