Water Pump: Relay Replacement

I have heard that Intellitec has a high amp LATCHING relay. Here is a Foretravel bulletin about one idea: Bulletin Number: B001000.001

Publishing Number: 26

Foretravel Service Bulletin

Due to the decreasing availability of the Siemans® latching relay, it has been decided that it will be replaced with the Intellitec® radio switch monoplex. 

This radio switch monoplex has proven to be a reliable replacement for both the water pump and water fill latching relay. Although it is physically larger, it should mount in the same location or in very close proximity.

Wire as follows:

  • 10ga. Red from the circuit breaker. Remove from terminal 56,  install on J2.
  • Remove and discard jumper wire between terminal 56 and terminal 30.
  • 14ga. Red from 56b on latching relay to J3 (wire to load).
  • Green wire from “S” terminal on latching relay, to J4 (switch signal).
  • J5 is ground.
  • J1 is blank.

A better choice is to use a common Bosch type automotive 30 amp relay to carry the pump current. And use your regular latching relay to control the Bosch, so the little current flows through the latching relay. This is a common solution.

A close up of a device

Description automatically generated

How we replaced our water pump relay

Standard  Motor Products LR-35 relay

Relay is a latching type. Used for 1973 VW headlight, square back H4-1584cc, 1.6L F/I. and sunroof relay 1986-1987.

Relay is mounted on a 12-volt bay panel behind white fiberglass cover. Attached with a clip behind relay that fits into a hole in the panel. Held in place with an aluminum angle that keeps the clip in the hole.

  • Wire identifications:
    S  –  to momentary grounding with inside switches, green
    30 –  12-volt positive, white
    56 –  12-volt positive, white
    56b – to the water pump and water pump on LEDs, white
  • Remove 12-volt power at the circuit breaker.
  • Remove wires from the relay.
  • Remove screw holding aluminum angle.
  • Pull relay up toward the ceiling, then pull out of the hole in the panel.

Use caution with tools and metal parts as the panel is grounded next to the positive rail. Reverse to install a new relay.

We replaced an original working relay and will keep the original relay as a spare part.

Our coach came from the factory with only one water pump switch and it was in the kitchen.

For a new bathroom water pump switch, I ran 3 new wires from kitchen to bath. Since our bath sink is on the same wall as the kitchen sink, wires were easily run between the two places along the floor within the cabinets.

For a new water bay water pump switch, the 3 new wires were run from latching relay in big bay. Any wires of about size 16 or larger are probably fine.

LED will indicate that the pump latching relay is energized.  If LEDs are not used, only two wires need to be run.

I plan to run another 3 wires from the kitchen to the front door area, so I can easily turn off the water pump when we leave our coach, to prevent water damage from a leak while we are gone. Switches are momentary 2-pole normally open switches and can be small Radio Shack switches or matching Foretravel switches from an RV parts store.

Multiple switch plates can be purchased from RV parts places, Camping World, Foretravel, etc.

LEDs are 12 volts and are available from Radio Shack, etc. by Barry and Cindy 1997 U270 36′ 3/29/12

I had a problem with the water pump relay on my recent trip.

This is a 2003 U295, and all of a sudden the water pump relay refused to actuate.

Pushing any of the switched only caused a slight flicker on the LED, but no CLUCK of the relay actuating.

I checked all the places I could think of, then called the factory.

The relay is behind that screwed-in panel in the bay under the driver’s seat. It is unmarked, and I only verified it by shorting the switched terminals and hearing the water pump come to life. This was not all that risky since all the other relays in that area were normal automotive types… this was the only oddball.

It is an oddly-shaped white plastic box with a bunch of wires attached. I discovered that it has a manual override. There is a push-button of sorts.  Pressing it alternates between activating and deactivating the relay.

I thought I would just live with the pump relay on for the remainder of my trip, but tried the switches again after manually toggling the relay a few times, and all is well now.

So, the same problem happens to you, try the pushbutton.  It might reset the thing so it works correctly again.

BTW, mine has two sets of switched terminals.  If one set burns out, it would be easy to move the wires to the other set. Tom Lang 2003 U295

That second set of terminals maybe for the freshwater tank fill.  My 2000 U320 had 2 separate relays – one pump and one fill.  The pump relay failed;  after a phone call with James Triana, simply moved connections temporarily over to the tank fill relay so the pump would work. I finished the trip and replaced the failed relay when I got home. Regards to all, John Lang 2007 Nimbus

On my 96 U320, the relay is in the large central bay, driver side, upper right behind a fiberglass cover. It right next to it is an identical relay that is used for the fill valve. I switch the 2 as a temporary measure (since a previous owner had removed the fill valve and put in a manual gate valve). Although you might just tap on it with a screwdriver and sometimes this will knock the contacts free.

I have several of these relays in my coach, they are also used to operate the 2 and 3-way lights inside the coach. Anyway, The VW relay #DNI 0127 (older VW # 111 941 583) is the identical switch and Foretravel uses the same part number. If you take both part numbers to Napa one of them should work for you.

I bought mine online through Kirkham motorsports 1(800)859-0923.  I bought 3 of them for a discounted price of around $18 each.  (I needed 2 and figured a spare would be a good idea) Bob 96 U320

On our 97 we were able to get a relay from Carquest. #56-2470 don’t know what it was listed for but it works for us. We took the old one down to the parts store and they crossed it over. Try any good auto parts store.

Just checked with parts man at the Blue and Yellow auto parts store there #ECH-AR284 he said they are for sunroofs. About $30. Pamela & Mike 97 U 320

In our case, the relay is located in the compartment just to the rear of the battery compartment on the forward bulkhead on the driver’s side. Dirt simple to replace, and works as it should. Dave & Barb Jenkins 1999 U320 40′

My ’99 U320 uses Finder 20-2190120000 relays for the water pump and water fill latching relays. Bob McGee 1999 U320