Rear Wiper Motor Relay Circuit Open
There's no signal to the rear wiper motor relay.
Heads up: this code wasn't in our hand-written library yet, so DiagCoach AI built this page on the fly. Double-check critical specs against service info before condemning parts.
What it means (plain English)
The rear wiper isn't getting power because the relay circuit is broken or disconnected somewhere along the line.
What the computer is actually seeing
The body control module (BCM) looks for a voltage signal (around 12V) from the rear wiper switch when activated. If it doesn't see that signal, it sets the B1593 code.
What a healthy reading looks like
The voltage at the rear wiper relay should be around 12V when activated, and continuity should exist in the circuit when the relay is supposed to be closed.
Guided diagnostic — the DiagCoach way
Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.
- 11. Check the wiring and connectors leading to the rear wiper motor and relay for any visible damage or disconnections. Repair as necessary.
- 22. With the rear wiper switch on, measure the voltage at the rear wiper relay. You should see around 12V. If not, check for continuity in the wiring back to the BCM.
- 33. Test the rear wiper switch for proper operation; use a multimeter to check that it closes the circuit correctly.
- 44. If all wiring and the switch are good but the code persists, consider replacing the rear wiper relay next.
Common causes
- Open circuit or broken wire in the rear wiper relay circuit
- Faulty rear wiper switch
- Defective body control module (BCM)
Typical repair cost
$$
Related codes
Frequently asked questions
Can I drive the vehicle with this code active?
Yes, but the rear wiper won't function until the issue is resolved.
Will this issue come back after repair?
If all faulty connections are fixed and parts replaced properly, it shouldn't come back.
Why does this relate to other codes?
These codes reflect related issues within the same relay circuit or electrical system.
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