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dogcatcher · 11-28-2012, 10:20 AM

location of pre heat relay? I know where solenoids are located but cannot find relay.

Jim_HiTek · 11-29-2012, 09:52 AM

Sorry that no one has given you a location Dogcatcher. But I have a question for you. What is a pre-heat system? Is it something that's suppose to pre-heat air going into the Turbo?

Would I have one on my older '94 Cummins? I don't think so as nothing in any of my owners manuals mention anything about a pre-heat device. I do have a block heater but that's 120Vac so plugs into an outlet and doesn't need a relay.

dogcatcher · 11-30-2012, 09:25 AM

JimHiTech:: some diesel engines use glow plugs & others use a Heat Grid located in the intake manifold,such as mine. I think it may be energized by the ECM (computer) but am not sure.

Jim_HiTek · 11-30-2012, 09:53 AM

What I've been reading for years on this and other RV forums is that modern RV diesels don't use glow plugs...the gensets do, but not the engine. A heat grid though...actually, don't recall hearing about that device, so failure must be pretty rare. Doubt I have one of those on my engine as I can't see any wires going to the turbo, before the turbo, or anywhere around the intake manifold. Something I guess I don't have to worry about.

Many of these rigs have relays in the BCC (Battery Control Center), along with some fuses. Have you checked in there for a blown fuse? Or for relays?

Did the rig come with a Cummins book? Or the chassis book?

(I'm surprised no one else has jumped in here with some expert advice).