No heat!HELP!

I just bought a 95 Sonoma and on the way home the heater turned on about half way.That was the only time it worked at all in 2 weeks.The wierd thing is that when you turn the switch to put it on the speedometer quits and the brake light comes on.Eventually the brake light goes out and the speedo starts to work again.The blower does nothing and you can feel a small amount of heat at highway speeds.It is now 3 degrees outside so I would appreciate any input to help me get this fixed.Thanks.

sounds like someone has messed with the wireing on your truck and done a piss poor job at whatever they were doin, i would get like a hauns and start looken at all of the stuff effected, the break scheme and guage cluster, maby ask for an electrical scheme from people here, best of luck to ya, the wireing can be a hassle but take your time and im sure you;ll manage

Electrical can be tough, or costly to fix. If you bought it from a dealer try bringing it back to them to fix. Most places have warenty laws even for used cars, especially when safety is involved (brake lights is safety to me)

yea COLDNESS is safelty too here in chicago they don't want gas compaines turing off heat NO matter What at least through winter might be electircal u can just buy the HOLD harness with each wired label instead of trying to figure out whats what

I would look to grounds first. The blower is grounded to the firewall. Are the grounds from the engine block to the firewall in good shape or connected?

It could be your relay on the left side of your firewall standing in front of the truck looking at the motor I don't know about your brake light or your speedo. but the same thing happened to me in my 2001 S-10 only mine was the high output, and the blower part of the relay.