99 low coolant now NO HEAT!

99 Silverado 96,000 Miles. the low coolant light came on, so i added some of the PINK stuff to bring it up to recomended level. Next time I drove the truck I noticed I now have no heat? I found that there is a service bulletin for it, which goes on to say theres a problem with the cap. I removed the cap and replaced and still have the same results. NO HEAT! Does anyone have any ideas on this? What should I do?

Thanks
PS I will need the heat soon up here in NewEngland.

can you smell antifreeze inside the cab of the truck? Check to feel for moisture up underneath the dash. If you smell antifreeze or feel the moisture it could be your heater core. Is there any heat at all coming from the ducts? Make sure that ac is turned off and that you turn the temprature up.....just making sure...
Has the truck been running hot or cold?

Thanks for the ideas. But no there is no smell of antifreeze nor is there any dampness on the mats. AC is off and the temperature setting is all the way on hot. Truck has been running normal also.

I found this posting on General Motors Technical postings.
1999 19FEB99 CUSTOMERS MAY COMPLAIN OF COOLANT LEAKS, LOW COOLANT LIGHT 'ON', OVERHEATING, NO HEAT, NO START, OR ODORS EMITTED FROM THE AIR CONDITIONING SYSTEM DUE TO THE COOLANT RECOVERY TANK PRESSURE CAP NOT FUNCTIONING PROPERLY. *TT

But I am not sure what they mean by RECOVERY TANK PRESSURE CAP NOT FUNCTIONING PROPERLY?

Recheck your coolant level, could have sucked up all you gave it and still be low... FYI, NEVER mix green and pink/orange. You will get a mess you wont soon forget.

camaro is right.... also I dont know about the chevy trucks, but I have a late 90s car and it has a bleeder valve on the termostat housing....if the trucks have the same valve make sure to bleed the coolant until it comes out the valve. I had a hell of a time with my vehicle over heating an no heat through the ducts one day because I had no idea that valve was there...... I felt like a jackass once someone pointed it out to me. Hope your problem gets fixed before winter.