Car Window Goes Down but Not Up: Relay Diagnosis Guide

Your car window rolls down just fine, but pressing the up button does nothing. You're left with an open window and a real problem especially if rain is in the forecast. When the down direction works but the up direction doesn't, the power window relay is one of the most common culprits. Knowing how to diagnose this relay issue can save you from an expensive shop visit and get your window closing again within an afternoon.

Why does my car window go down but not go back up?

Power window systems use a reversible motor. The motor spins one direction to lower the glass and the opposite direction to raise it. The direction is controlled by reversing the polarity of the electrical current sent to the motor. A relay, switch, or module handles this polarity reversal.

When the window goes down but won't go up, the motor itself is usually still working. The problem is in the control side the part that tells the motor to reverse direction. A failed relay, a faulty switch contact, a broken wire, or a bad ground on the "up" circuit can all cause this specific symptom.

This is different from a window that moves slowly or stops partway. Those issues often point to a wearing window motor or a binding window regulator that may need testing with a multimeter. A window that works in one direction but not the other narrows the diagnosis significantly.

What does the power window relay actually do?

The power window relay acts as a high-current switch controlled by a low-current signal. When you press the window button, the relay closes a circuit that sends battery voltage to the window motor in the correct direction.

Many vehicles use a single relay for the "up" function and a separate relay or the switch itself for the "down" function. Some systems use a single relay with internal contacts that handle both directions. When one set of contacts fails, the motor gets power in only one direction.

Relays wear out over time. The internal contacts can corrode, pit, or weld themselves in one position. A relay that has failed in the "down" position (or whose "up" contacts are burned) will give you exactly this symptom: the window drops fine but refuses to climb.

How do I know if the relay is the problem?

Start by checking whether the issue affects one window or all windows. If only one window is stuck, the problem is likely local to that door's circuit the relay, switch, or wiring for that specific window. If all windows fail to go up, the issue may be a shared relay, fuse, or master switch.

Here's a quick way to narrow it down:

Listen for a click. Press the up button and listen near the fuse box or relay panel. A faint click means the relay is receiving the signal and attempting to engage. No click could mean a bad relay coil, a wiring issue, or a switch problem.
Swap the relay. If your vehicle uses identical relays for multiple functions (many use the same part number for horn, A/C, or other accessories), swap the suspected relay with a known good one. If the window starts working, you've found the problem.
Test with a multimeter. Set your meter to DC voltage. Probe the relay socket terminals with the ignition on and the up button pressed. You should see 12V on the output side. If you see voltage on the input side but nothing on the output, the relay contacts are not passing current.

You can also test the window switch wiring with the ignition on to rule out the switch before replacing the relay.

Could the problem be something other than the relay?

Absolutely. A few other failures cause the same one-direction symptom:

Window switch contacts. The switch itself has separate contacts for up and down. The "up" contacts can wear out while the "down" contacts still work. This is especially common on the driver's master switch, which gets the most use.
Broken or corroded wiring. The wiring harness that runs from the door jamb into the door flexes every time you open and close the door. Over years, the "up" wire can break internally while the "down" wire stays intact.
Bad ground connection. Some systems ground the motor through the switch. A corroded ground point will kill one direction while leaving the other functional.
Failed window motor (partial). Rare, but some motors develop a dead spot that only affects one rotational direction.

Check the wiring at the door hinge area before replacing the relay. Peel back the rubber boot between the door and the body and inspect each wire for breaks, corrosion, or green oxidation.

How do I test the power window relay with a multimeter?

Pull the suspect relay from the fuse box. Look at the diagram printed on the relay or in your owner's manual to identify the coil pins and the switch pins.

Test the coil. Set your multimeter to ohms (resistance). Measure across the two coil pins. A good relay typically reads 50–120 ohms. An open reading (OL) means the coil is burned out.
Test the contacts. With the relay removed, measure across the two switch pins. You should see an open circuit (OL). If you read continuity, the contacts are stuck closed which could explain why the motor only works in one direction.
Activate the relay manually. Apply 12V across the coil pins using a bench power supply or a 9V battery (for 12V relays, a 9V battery will usually still click the relay). While energized, check continuity across the switch pins. It should show near-zero resistance. If it doesn't, the contacts are burned.

For a broader look at motor-side failures, you can diagnose the power window motor with a multimeter to make sure the motor itself isn't part of the problem.

Where is the power window relay located?

On most vehicles, the power window relay sits in the under-dash fuse box or the under-hood fuse/relay box. Some vehicles put it inside the door, behind the door panel, as part of the window regulator assembly.

Check your owner's manual or the fuse box lid diagram. The relay is usually labeled "P/W," "WDO," or "WINDOW." If your car uses a body control module (BCM) to manage windows, there may not be a standalone relay the BCM handles switching internally, and diagnosis shifts to the module and its wiring.

What are the most common mistakes when diagnosing this?

Replacing the motor first. Since the motor clearly works in one direction, it's almost never the motor. Don't spend money on a regulator assembly until you've ruled out the relay, switch, and wiring.
Ignoring the fuse box diagram. Swapping random relays without knowing which one controls the windows wastes time. Always verify the relay position before pulling anything.
Skipping the wiring check at the door jamb. Broken wires in the door boot are extremely common and cheap to fix. A $0.50 butt connector can solve what looks like a $200 relay problem.
Not checking the master switch. On many cars, the driver's master switch can lock out all passenger windows. Make sure the window lock button isn't engaged before digging into relays.

What should I do next?

Once you've confirmed the relay is faulty, replacement is straightforward. Pull the old relay, push in the new one, and test the window. Most power window relays cost between $8 and $25 at any auto parts store. Match the part number printed on the relay body not just the socket shape since similar-looking relays can have different pin configurations or coil ratings.

If you swap the relay and the window still won't go up, move to the switch and wiring as the next diagnostic steps. The relay is the easiest and cheapest part to check, which is why it's the right starting point.

Quick relay diagnosis checklist

Confirm the window goes down normally but not up
Check if other windows are affected (narrow the circuit)
Make sure the window lock button is off
Locate the power window relay using the fuse box diagram
Listen for a click when pressing the up button
Swap the relay with an identical one to test
Measure coil resistance and contact continuity with a multimeter
Inspect wiring at the door jamb for breaks or corrosion
Test the switch output voltage if the relay checks out
Replace the faulty component and verify full window operation

Tip: Before you close everything up, run the window up and down several times and flex the door wiring harness by hand. An intermittent break will sometimes show up only under movement. Catching it now prevents a callback.

Reference: NHTSA Vehicle Equipment and Safety Standards