Can you please provide picture of GTM Info and FM Traffic status from nuvi 3490 where GTM36 work?
Then we can compare if is on working antena also write 4G/HD (this kanoups discover from picture).
Something is wrong but we dont know what becouse i found on net that on some nuvi 34xx FW 7.10 work GTM36.
Why Garmin add this GTM to LMT package if dont work and why take so long for Garmin tu create fix.
GTM25/35 use FW 300/320 but GTM26/36 use ver 2.10 i think that this is problem,becouse FW is to old and cant detect new GTM