Front & Rear washer relay mystery

[EmperorWatcher]

This one has us baffled. The front windshield washer on my 2004 XC70 with 173,000 mi. suddenly stopped working. The washer pump was replaced a year ago, so it came as a surprise. It finally dawned on me that perhaps it was a fuse! After a quick search, I learned that there is no fuse, but both the front and rear washers have relays, FM13 and FM14, respectively. Both relays (as well as FM11 & FM12) have the same part no. 9441161.

I tried the rear washer and it was working, so I switched those 2 relays. Yippee! the front washer worked! My logic indicated that I needed to replace FM13. I removed it and found a replacement at NAPA for $8.. Volvo wanted $23 - 32 for a TYCO brand, and the replacement from NAPA was FLOSSER (German made). TYCOs were available online for $5-40. I opted for the instock FLOSSER part at the NAPA store.

I then learned that both relays need to be installed for either washer to function. I put the new one in FM13, replaced the one in FM14 with the one that had been there. Rear washer worked, front washer didn't! So I switched them again. Front washer worked! I figured I'd gotten a bad relay, but I decided to pull the other 2 identical relays and try them out in FM13 and FM14 to test my conclusion about the bad part. No change. Rear washer worked, front washer didn't. I replaced FM13 with the relay that had been in FM14 and figured that I would rarely need the rear washer.

Why won't both washers work?!! What am I missing?

Many thanks!

[JRL]

I would look for a fallen off or broken hose

[billr99]

I would look for a fallen off or broken hose

Even with a broken hose, the OP should still be able to hear the rear washer motor and it should still activate the rear wiper. As it is, he indicates that both circuits are working properly when the one relay is used. Logically, this indicates that the relay is bad. Now the question I have as it isn't clear to me, did the OP try the two known good relays in FM13 and FM14? I'm thinking that the NAPA relay isn't really the right one or is faulty.

Cheers,

Bill

[EmperorWatcher]

Even with a broken hose, the OP should still be able to hear the rear washer motor and it should still activate the rear wiper. As it is, he indicates that both circuits are working properly when the one relay is used. Logically, this indicates that the relay is bad. Now the question I have as it isn't clear to me, did the OP try the two known good relays in FM13 and FM14? I'm thinking that the NAPA relay isn't really the right one or is faulty.

Cheers,

Bill

Yes Bill. Both washers work, when certain relays are installed. The mystery is that when I use other seemingly good relays, I can't get both front and rear washers to both work at the same time. By exchanging relays, I get one or the other to work.

Logically, the NAPA relay is the culprit, but when exchanged with other identical relays in the fuse box, both washers won't work (only one or the other). It doesn't make sense to me. I think I'll get another relay and try it out. Maybe there is some sort of "series" configuration that isn't correct with that NAPA relay. The relays all have printed circuit diagrams on them, which appear identical, with a variation on one of them.

Thanks for helping me think this one through!

[billr99]

Logically, the NAPA relay is the culprit, but when exchanged with other identical relays in the fuse box, both washers won't work (only one or the other). It doesn't make sense to me. I think I'll get another relay and try it out. Maybe there is some sort of "series" configuration that isn't correct with that NAPA relay. The relays all have printed circuit diagrams on them, which appear identical, with a variation on one of them.

That would be about the only logical thing left to try. I looked up what VIDA has to say on it and it looks like all the relays in that I Block (i.e. I-1 to I-16) are identical. Probably some insidious plot by Volvo to make sure folks only buy their blue-box labelled relays;).

Good luck,

Bill

[hoonk]

front windshield washer 2004 XC70 suddenly stopped working
The washer pump was replaced a year ago
perhaps it was a fuse, there is no fuse,
front and rear washers have relays, FM13 and FM14
I switched those 2 relays. the front washer worked!
I then learned that both relays need to be installed for either washer to function
- There are fuses, b10 for front pump and relay, b16 for rear pump and relay (under the hood)

You might simply have a bad ground (terminal 4 at the harness coming from the pumps/level sender) . Looking at the diagram current could back feed through the other relay, (the relays are shown in the off position, and relay post 87a goes to a different ground point than the pumps) and both relays would need to be in place for that to happen. The ground location didn't print but it's a communal wire bolted to the body at 31/1 - near the power steering reservoir.

To easily test, Create a temp jumper wire from terminal 4 to the body -


Or sometimes when things don't work right electrically - disconnect battery, clamp terminals together for a few minutes, then reboot the system. The CEM grounds the washer relays to activate the pumps - perhaps the CEM is confused :)


7798

[EmperorWatcher]

- There are fuses, b10 for front pump and relay, b16 for rear pump and relay (under the hood)

You might simply have a bad ground (terminal 4 at the harness coming from the pumps/level sender) . Looking at the diagram current could back feed through the other relay, (the relays are shown in the off position, and relay post 87a goes to a different ground point than the pumps) and both relays would need to be in place for that to happen. The ground location didn't print but it's a communal wire bolted to the body at 31/1 - near the power steering reservoir.

To easily test, Create a temp jumper wire from terminal 4 to the body -


Or sometimes when things don't work right electrically - disconnect battery, clamp terminals together for a few minutes, then reboot the system. The CEM grounds the washer relays to activate the pumps - perhaps the CEM is confused :)


7798

I gave it one last shot at rearranging relays before giving these latest suggestions a try.. I honestly thought that these latest ones were the cure. I took the Volvo/Siemens relay from FM11(AC clutch), moved it to FM13 (Front Washer), replaced it with the new Flosser, that I'd previously inserted in FM12. Then took the existing TYCO that had been in FM13, and inserted it in FM12. Both washers now work, and I believe the AC clutch is working correctly too!

Time will tell if that NAPA/Flosser relay is defective, but meanwhile, everything seems ok.

Thanks to everybody for your interest!