? for you blazer guys

[bogginjess]

Alright, well i have an 01 blazer and lately while driving it my speedo will bounce around and occasionally the brake light gauge will flash, when it first started happening it would only do it for the first mile or so down the road then be fine but now its all the time.  I'm pretty sure its just a speed sensor issue  but just wanted some input on if im right or not  before i go and drop $80 on one

[Jjay78]

double check your grounds for that circut