2007 TM-B Coach Batteries not charging while engine is running

[[email protected]]

Hi everyone. New to this forum. I have 2007 Tour Master B with Mercedes engine. I’m having an issue with the house batteries, they don’t get charged with the engine running, only when plugged to shore power or with the generator running. Meanwhile the chassis batteries are being charged with the engine running, so I know that the alternator is working fine (13.8V). It all started after we were camping for 10 days and on the way back i noticed that issue. I have checked all known related fuses and circuit breakers, but I still don’t see any voltage present at that yellow wire going to the isolation relay, which I replaced about 2 months ago due to intermittent not latching problems. That’s how I know that there should be 12-13v signal present at the yellow wire terminal. Please shine a light if you know more about it. Both house batteries are new (2 months old) and holding charge, no excessive drainage (13.6V when plugged to shore 50A power). I have ruled out so far that my problem is that the IRD Module, since the IRD relay operates when using the Aux Start switch on the dash. Where is the location of the IRD module and its Main relay? Thanks for your inputs.

 

[Chuck v]

Attached is the diagram for the DC wiring on your coach. The coach IRD and the main IRD are both driven/controlled by the IRD module and control relay -- yours may have failed.


Chuck

 

[[email protected]]

Thank you Chuck. Do you know the location of the IRD Module and the Main relay? I cannot seem to find them in the rear compartment and by the batteries. What do they look like?

 

[Chuck v]

I do not have the coach any longer, so will go by memory and few pictures in my files... The BIRD module is most likely made by Intellitec on your coach and look like this:
https://www.rvautoparts.com/products/00-00839-000-intellitec-battery-isolator-relay-delay-delays-the?currency=USD&variant=45142620176685&utm_source=google&utm_medium=cpc&utm_campaign=Google%20Shopping&stkn=b45cc860ded1&gad_source=1&gclid=EAIaIQobChMI68fehOOhhwMVZA-tBh1UuA5iEAQYBCABEgLMkfD_BwE


The coach IRD relay is the silver one in the mid lower part of your picture...the main ird relay is the very large contactor over on the right lower corner if the image. I do not see the control module in the image...



Sorry I cannot be more specific. Try tracing back the yellow wire to see where it goes and you may find the BIRD module.



Chuck

 

[Chuck v]

This thread says the BIRD module may be in the front bay (see text and pictures...)


https://www.gsowners.com/forums/showthread.php?t=4728&highlight=BIRD

 

[[email protected]]

Thanks Chuck. I will take a look in the location that the guys from the other post mentioned and will let you know what happens.

 

[THenne1713]

Thank you Chuck. Do you know the location of the IRD Module and the Main relay? I cannot seem to find them in the rear compartment and by the batteries. What do they look like?

Often, relays/ components are mounted in a compartment NEXT to coach batteries= within 14-24"= close but protected from battery acid fumes/ corrosives. I.R.D./ B.I.R.D is usually a rectangular box with smaller wires that (go to/ control) the coil on a solenoid w/ larger battery cables. You can search "I.R.D. RV control" on eBay or Amazon and maybe find pictures. I do not see one in your picture, might be just off camera, or in another compartment? E.g. On Econoline chassis, charge solenoid on driver side firewall, but battery on passenger side.