2011 GL350 - headlight washer system
Thread Starter
Junior Member
Joined: Jun 2020
Posts: 42
Likes: 4
From: Midland, TX
2011 GL350
2011 GL350 - headlight washer system
Hey Y'all,
2011 GL350 - troubleshooting headlight washer system, and here's what I got:
Symptoms:
- headlight washer pump engages every 10 sprays with headlights on
- the duration of spray seems ok, nozzles pop but no fluid comes out - should there be a check valve somewhere to stop the fluid from draining back down to tank?
Troubleshooting:
- Headlight washer pump - replaced with new one
- Checked hoses coming out of pump into nozzles - no obstructions - water/fluid coming through
- Removed nozzles, cleaned and confirmed they are spraying (used pressurized air and later mixed with pressurized water - nozzles pop out and spray fluid - no obstructions)
- I supplied external 12V power to the pump and with a longer power supply - water comes out of nozzles and sprays
Some questions I have are:
1. Do MB nozzles have built in check-valves?
2. Should there be a check-valve in line after the pump? - I can't locate one on mine. There is a Y-split but it's just a split not a check-valve between nozzles and pump
Before I start throwing new parts at the system, just want to understand it a little better. Is it possible that pump duration is too short, that fluid never comes out of nozzles? or is it simple as check-valve to make sure that fluid always stays in the hoses.
Lastly - when I do the spray headlights on and when nozzles pop out, there is no internal leak, no fluid is coming through the nozzles and outside.
To me it feels like:
- spray duration is too short and fluid never makes it to the nozzles
- hoses get empty (drained) between sprays (10x washers) and pump fills up the hoses but fluid never gets into the nozzles
2011 GL350 - troubleshooting headlight washer system, and here's what I got:
Symptoms:
- headlight washer pump engages every 10 sprays with headlights on
- the duration of spray seems ok, nozzles pop but no fluid comes out - should there be a check valve somewhere to stop the fluid from draining back down to tank?
Troubleshooting:
- Headlight washer pump - replaced with new one
- Checked hoses coming out of pump into nozzles - no obstructions - water/fluid coming through
- Removed nozzles, cleaned and confirmed they are spraying (used pressurized air and later mixed with pressurized water - nozzles pop out and spray fluid - no obstructions)
- I supplied external 12V power to the pump and with a longer power supply - water comes out of nozzles and sprays
Some questions I have are:
1. Do MB nozzles have built in check-valves?
2. Should there be a check-valve in line after the pump? - I can't locate one on mine. There is a Y-split but it's just a split not a check-valve between nozzles and pump
Before I start throwing new parts at the system, just want to understand it a little better. Is it possible that pump duration is too short, that fluid never comes out of nozzles? or is it simple as check-valve to make sure that fluid always stays in the hoses.
Lastly - when I do the spray headlights on and when nozzles pop out, there is no internal leak, no fluid is coming through the nozzles and outside.
To me it feels like:
- spray duration is too short and fluid never makes it to the nozzles
- hoses get empty (drained) between sprays (10x washers) and pump fills up the hoses but fluid never gets into the nozzles
MBWorld Fanatic!
Joined: Sep 2005
Posts: 6,189
Likes: 242
From: Albuquerque
'10 CL550, '12 GL550
Illustrated parts breakdown ... https://nemigaparts.com/cat_spares/e...24/63l/86/030/
