RZA ZAR

So I recently did s carbonator swap on my 1990 2500 single cab and it was all working fine nothing wrong and then yesterday when I was leaving for work I went to turn up my heater from medium to high and it switched over for maybe a minute. Then it shut down the digital display and the fan. I checked the fuses and nothing was blown is there maybe another place a fuse could be besides the fuse box in the cab? Or is it something else?

oilcanhenry

Can you feel any heat from the climate control box or from outside air coming in at all? Have you checked the relays and fuses located in the engine bay drivers side?

RZA ZAR

There is hot air still coming through the vents and I don't have a fuse box under the hood at least that I could find

oilcanhenry

Chevrolet must have changed things since 1990. My 1998 K-1500 has the fuses both in the cab and on the external box mounted on the drivers front fender.Probably has something to do with the change-over to OBD II in 1995-1996. If the climate control display is not visible it may have gone bad or possibly the resistor is not working.

RZA ZAR

That's all that's on the driverside of the engine bay

RZA ZAR

So I should check to see if the head unit itself went bad

oilcanhenry

Yes, that is how I recall that the Chevy pickups looked in 1988-1990. The secondary fuse and relay box is located about where the washer reservoir is now, which on my pickup is located on the passenger side up next to the firewall.

oilcanhenry

Yes, I would. After all its almost 30 years old so anything can go south in that space of time.

RZA ZAR

Yeah true and I won't be able to check it until this weekend so if you have any other ideas or something else to try just post it here and I'll let you know how it goes when I test it