Speedometer

i have same issue...speedometer quit over 6 months ago - needle does not move at all. Now my security light comes on and off with my keyless remote door lock/trunk working sometimes yes sometimes no(changed batteries lots) and to top it now at times when i turn ignition key nothing happens at all - sometimes if i unlock doors, click the keyless remote buttons. lock doors etc....then wait car starts fine. I know this is electrical and need any help on parts. 2005 chev monte carlo have 89000 miles on car and dealer per phone says cashy repair/need to tear out dash !!! Please help with any ideas thank you