Hello Kurt, the author of this thread
I guess you went past your truck's Fording Depth which is 1/2 of your wheel height. I wouldn't worry about the those light signals as it may have just been a coincidence at the time. You can however do a simple check on some possible electrical wiring in the engine bay that the flood water may have reached.
I would suggest that your repack your wheel bearings since
going through that 200 meter distance will get to the grease real good. Have the rear drum brakes cleaned too during this service. Other than those, the truck underchassis should be alright.
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