Damage to the windshield washer pump on your 626 most often happens from water contacting its electrical connection and causing a short circuit. A crack in the washer fluid reservoir is typically the culprit. Driving through large bodies of water while it's raining or just after can splash water into the undercarriage and cause damage to the pump, too. The windshield washer pump on the Mazda 626 mounts against the firewall just below the washer fluid reservoir. You can replace the pump right at home with a few tools in 30 minutes or less.
Pull the bonnet release lever and raise the bonnet on your 626.
Loosen and remove the negative battery cable from its post on the battery with a socket wrench. To identify which of the two cables connected to the battery is the negative, look for a small minus sign on top of the battery case next to the cable. The cable should be black. Once you have removed the cable, use a roll of electrical tape to wrap the metal terminal at the end of the cable, then position it away from the battery.
Slide a drain pan under the car directly in line with the washer fluid reservoir. Open the filler cap on the washer fluid reservoir. Reach down beneath the reservoir and feel for a rubber hose connected to the its bottom. Pull the hose off the reservoir and allow any remaining washer fluid to drain into the pan.
Disconnect the small push-on power wire from the reservoir by pulling it straight off its connection.
Remove the two mounting bolts on the left side of the reservoir and lift the reservoir out of the car. Place the two bolts in your pocket for safekeeping and set the reservoir to the side of the work area.
Disconnect the wiring harness plug connected to the washer pump by hand, and then wiggle the pump away from the firewall to free it. The pump doesn’t have any bolts holding it to the firewall. It’s held in place by a large rubber grommet that mounts on a nipple on the side of the pump. Your new washer pump will come with a new grommet and fluid hose, so you don’t have to save either from the old pump.
Attach the fluid hose and grommet to your new washer pump if it wasn’t already pre-assembled. Mount the new pump into position on the firewall and wiggle it while pushing inward until you see it fully seated against the firewall. Plug the wiring harness back up to it.
Insert the fluid reservoir down into position ready for mounting. Before you return its mounting bolts, reconnect the rubber hose from the pump back to the nipple on the bottom of the reservoir. The hose simply pushes back on--no tools required.
Reconnect the push-on power wire to the fluid reservoir and thread both of the reservoir’s mounting bolts by hand. Set your 1/4-inch drive torque wrench to 60 in-lbs. and completely tighten both of the bolts.
Remove the tape on the negative battery terminal. Connect the cable back to the battery and tighten its bolt by hand until snug. Set your 3/8-inch drive torque wrench to 12ft-lbs. and secure the cable to the battery. Refill the washer fluid reservoir and check the windshield washer pump's operation.
While you have the washer fluid reservoir removed, check it for any visible cracks. Clog the nipple at the bottom of the reservoir and then fill the reservoir with water to check it for leaks. If you happen to have some food colouring on hand, place a few drops of it into the water in the reservoir. This will help you to more easily identify a crack. Red or green food colouring will work best.