[DeTomaso] Techno Question: Electrical gremlin help

[Charles Engles]

Dear Forum,

          I am faced with a new gremlin.  A variable gremlin, not a non functioning one.   I installed some new GT4 taillights from Larry Finch and made sure to ground them well.  They have been working fine.  Now, on a two hour trip yesterday, they didn't work at the start and after an hour, they started working.  Today,  they started with a one or two blink response (same on both sides) and then quit.  They would repeat this about three or four times and quit altogether.   On the return trip home (after the engine and the electrical system were "hot" [??} ), they began working again.   I just tested them in the garage and they will flash about four or five times and then cease.    After about four tries, they cease altogether.   
         Could this variable, intermittent malfunction be due to the dreaded ground problem at the legendary common ground bolt rumored to lurk up under the dash in "no man's land"??

              I hate electrical problems,  Chuck Engles