98 Blazer heater core replacment (I just did it)

[maxpower_hd]

I'm going to be changing the heater core in my buddies S10 Blazer. It sounds like a PITA but within my abilities. His is a 1995. Is it the same thing pretty much?

Thanks

[bigdinz]

I thought I'd contribute some pictures. The instructions were great to have for this job. Almost done....





If any of you that have done this before can help me out I got a small problem. Maybe one of you know where the connections in the picture below go. They are all the way on the right side and I can't for the life of me remember or figure out where they go.

[srbianats]

I think the connector on the left goes to your air bag. I don't remember what the connector on the right goes to. Maybe it goes to the top of the heater box assembly.

[bigdinz]

I appreciate the input but I'm positive that all the airbag connections are yellow. I for the life of me do not remember any connections to the heater box. I guess I'll have to undo all that I have put back so I can figure it out. I just do not see anywhere they could go. All the electronics have connections and these 2 look pretty important to me. This really blows, I was hopeing to find the connections while reinstalling everything but I guess not.

[bigdinz]

I half put everything together to see what problems I may have and of course there are problems.
1. My airbag light is on (I made sure all connections were good).
2. Brake light is on.
3. My defroster/floor doesn't work (only blows through vents).

I am pretty adept at anything mechanical but I cannot figure out where those wires go. I even took the whole dash out again and I still cannot find the connections.

HELP PLEASE!!!!!

[Southern Comfort]

I have the schematic for a 99 S10 which should be the same as yours. I don't know if you know how to read a schematic , but I can email it to you. Email me at [email protected]
Thanks
SC

[bigdinz]

***UPDATE***
I found where those plugs went. The one on the right goes to the top of the heater box (srbianats..you were right!) The one on the left goes to that junction box on the outside front of the heater box (right in front where it splits). Now with all connections good I am still getting the airbag light and now my dome lights won't go out when all doors are shut. !!!!!Lord help me!

[lefthandscrewdrivr]

hey , do u know where i can get a diagram to change my 96 blazers heater core...cuz i think our years may be different . not sure..any help from an yone would be appreciated..if you can help my email is [email protected] ..


thanks,
"girl in need of heat"

[bigdinz]

--UPDATE--

I found all my problems and they were all minor ones (not putting fuzes back in...LOL). Thanks for the help people.

[briley1207]

Do you have any suggestions on a 94, I need to replace mine..

[marly87]

Sorry, I got rid of my money pit last year! I will say that my friend changed it out for me for $100, compared to the $1200 the repair shop was going to charge. It took him and his cousin like 4 hours, compared to the 8 the shop quoted me. I guess my advice is, if you can do it yourself or have a mechanic friend do it, it'll save you a lot of money.

[travellerguy]

Hello - I like most other people have gotten the dash apart and am staring at the black box containing the heater core. It's staring back at me and I think laughing.

I've removed the two bolts in the engine compartment and the nut next to the heater core hoses (engine compartment) but haven't cut into the box that says "for service cut me - then you shall repent and call gm and pay through the nose to find the one hidden bolt"

so... any suggestions? I really don't want to cut up the plastic that says cut me. Where is that last bolt?

[bigdinz]

Hate to break it to you but it's under that spot. You gotta cut it. I patched the hole with a plastic seal kit from advanced auto. It looks similar to a fiberglass patch but it dries black. Good luck.

[travellerguy]

nah not at all - hey thanks a lot for the quick reply!

Alright... before I do the cutting - the arrow in your picture (the big arrow) is pointing down near the base of the evaparator box -- but cut here is on top.

Did you cut the top of the box? (or somewhere along the side)

thanks again

[NINFan]

Originally Posted by travellerguy

nah not at all - hey thanks a lot for the quick reply!

Alright... before I do the cutting - the arrow in your picture (the big arrow) is pointing down near the base of the evaparator box -- but cut here is on top.

Did you cut the top of the box? (or somewhere along the side)

thanks again

i just did this on a '99. it's different, but pretty close. i wouldn't bother cutting at the 'cut here for service' place. that whole housing cover is a soft plastic material, and you can cut it easily enough with a razor knife, but i found it was easier to just undo the cover and move it out of the way. first, remove the 2 10 mm bolts holding the cover on to the firewall (one needs to come out to get the heater core out anyway). disconnect the electrical connector to the blower resistor. there are 6 7/32" bolts holding the 2 pieces of the plastic cover to each other. remove the top 2 and the 2 closest to the front of the car. you'll be able to bend the plastic cover out of the way. then remove the 3 bolts holding the blower resistor in place and remove it. you'll be able to get a 10 mm universal socket on a long extension down into the A/C compartment and remove the last bolt. just be careful not to drop it, although if you did, you'd be able to get it out once you remove the heater box anyway. this is the bolt that the fat arrow is pointing to.