Help with Slide and Awning Safety Interlock Circuit***

[MarkN1969]

Working on a 2012 Thor 29.2 Class A Gas Motorhome Vin # (last 8) C0A02705
In the Desert and it's getting hotter by the day. I have chased it down to the two interlock relays staying energized all of the time even with the key out of the ignition, parking brake on and in park. Called Thor they sent me wiring diagrams but nothing on the interlock wiring. I need to find out where the yellow wire in the wire loom is getting it's power from to signal the relay to engage. I can deactivate the relays and slides and awning work perfectly. I want to fix the problem and find the source but no diagram. Praying someone has had this issue or knows this system. Please help if you can. Thanks in advance!

 

[Domo]

Could I suggest you install a manual switch to override the misbehaving circuit? That way you can control while away from home and do the exhaustive troubleshooting when at home or some cooler location?

It is very rare that a comprehensive (accurate) wiring/cabling diagram exists for (nearly) any brand of RV.

In some cases you may find that you simply have to abandon the original wire and run a new one... Or, read on for what I do when troubleshooting...


Bring CRC contact cleaner and lubricant, meter, crimpers and dielectric grease with you when troubleshooting. Remove all the related plugs from their sockets, spray both with CRC and then insert+remove about three times to help break any corrosion. Continue, including removing fuses or 12 relays/breakers from sockets and dowsing their contacts and sockets with CRC. While you're doing this, look for crimp-on connections and re-crimp them (or replace if you see green/oxidation of the wire). Trace all ground wires to the ground block or chassis. Remove them, scrape any dirt or paint off, clean the contact and bolts and put it all together.

 

[Tulecreeper]

Could I suggest you install a manual switch to override the misbehaving circuit? That way you can control while away from home and do the exhaustive troubleshooting when at home or some cooler location?

It is very rare that a comprehensive (accurate) wiring/cabling diagram exists for (nearly) any brand of RV.

In some cases you may find that you simply have to abandon the original wire and run a new one... Or, read on for what I do when troubleshooting...


Bring CRC contact cleaner and lubricant, meter, crimpers and dielectric grease with you when troubleshooting. Remove all the related plugs from their sockets, spray both with CRC and then insert+remove about three times to help break any corrosion. Continue, including removing fuses or 12 relays/breakers from sockets and dowsing their contacts and sockets with CRC. While you're doing this, look for crimp-on connections and re-crimp them (or replace if you see green/oxidation of the wire). Trace all ground wires to the ground block or chassis. Remove them, scrape any dirt or paint off, clean the contact and bolts and put it all together.

^^^ That ^^^

It is not uncommon for RV manufacturers to use whatever wire they have laying around when running the wiring, so color is not an industry standard...or any standard for that matter. They may start out the week with everything color coded, but by Friday they may have more brown wire left than anything else so everything that day is brown. I've seen blue, green, and purple randomly spliced together. You can pretty much assume that white is ground, but everything else may be hot.

 

[Gary RV_Wizard]

I need to find out where the yellow wire in the wire loom is getting it's power from to signal the relay to engage. I can deactivate the relays and slides and awning work perfectly. I want to fix the problem and find the source but no diagram. Praying someone has had this issue or knows this system. Please help if you can. Thanks in advance!

I'm afraid you are just going to have to dig through it. It's even possible your wiring is different color and routing than others, whether accidentally or for the reasons Tulecreeper stated.

Does your diagram indicate what those interlock relays represent, e.g. park/brake set or ignition off? Sometimes you can start from the other end if you know where it is.

 

[Wasillaguy]

It's possible that 12v is hardwired to the relay coil and it's the ground side that is opened/closed to control the relays. If that control wire (which likely runs to ignition switch wire) gets pinched somewhere along it's routing, relays would stay pulled in all the time.

 

[MarkN1969]

The yellow wire that feeds two out of the three relays has 12 volts to them constantly. That yellow wire is the wire which feeds 12 volts to the coil in the relay causing the relay to be energized. This is causing the wire that goes to the center terminal on the wall slide switch to not have 12 volts. When I remove power from the yellow wire to the relays the slide and awning work as they should. I'm going back today to chase the yellow wire back to it's power source or switching source. I was hoping that someone has had this issue with a Thor Motorhome before and might be able to suggest where to find the end of the wire or a location to start at. Thanks for all of your inputs and if you have any more ideas I would greatly appreciate them. I will be sure to post my findings when completed.
Mark

 

[MarkN1969]

Could I suggest you install a manual switch to override the misbehaving circuit? That way you can control while away from home and do the exhaustive troubleshooting when at home or some cooler location?

It is very rare that a comprehensive (accurate) wiring/cabling diagram exists for (nearly) any brand of RV.

In some cases you may find that you simply have to abandon the original wire and run a new one... Or, read on for what I do when troubleshooting...


Bring CRC contact cleaner and lubricant, meter, crimpers and dielectric grease with you when troubleshooting. Remove all the related plugs from their sockets, spray both with CRC and then insert+remove about three times to help break any corrosion. Continue, including removing fuses or 12 relays/breakers from sockets and dowsing their contacts and sockets with CRC. While you're doing this, look for crimp-on connections and re-crimp them (or replace if you see green/oxidation of the wire). Trace all ground wires to the ground block or chassis. Remove them, scrape any dirt or paint off, clean the contact and bolts and put it all together.

Thank you for your reply. I bypassed the two relays for the slide and awning until I have more information on the circuit. I managed to trace the yellow wire up to the front of motorhome and it goes into the Battery Control Center. I did the troubleshooting procedures to the BCC Ignition and accessory relays in the BCC control board and they are functioning correctly. I may look at the ground wire to the Interlock relays and see where they lead me. Thanks again!

 

[MarkN1969]

Thank you for your replys. I bypassed the two relays for the slide and awning until I have more information on the circuit. I managed to trace the yellow wire up to the front of motorhome and it goes into the Battery Control Center. I did the troubleshooting procedures to the BCC Ignition and accessory relays in the BCC control board and they are functioning correctly. I may look at the ground wire to the Interlock relays and see where they lead me. Thanks again!

 

[MarkN1969]

I'm afraid you are just going to have to dig through it. It's even possible your wiring is different color and routing than others, whether accidentally or for the reasons Tulecreeper stated.

Does your diagram indicate what those interlock relays represent, e.g. park/brake set or ignition off? Sometimes you can start from the other end if you know where it is.

I doesn't tell me what controls the relays. The water pump relay is controlled by the water pump switch located inside the coach control panel along with tank level indicators, generator start switch, etc.

 

[MarkN1969]

It's possible that 12v is hardwired to the relay coil and it's the ground side that is opened/closed to control the relays. If that control wire (which likely runs to ignition switch wire) gets pinched somewhere along it's routing, relays would stay pulled in all the time.

Yes that could be possible.