I think possibly that was the vacuum canister??
The default mode is defrost when it loses vacuum to the heater controls under the dash. Thats why it stays on defrost. Check the vacuum line going thru the firewall (passenger side) and there is also a check valve in that vac hose that could be leaking. Basically it comes down to this. The vacuum reservoir stores vacuum so when you give it full gas and the engine vacuum drops, it doesn't affect the dash controls. So you just need to check the vacuum line coming off the engine, then goes to the vac reservoir, then to the firewall to the controls....somewhere in there it is leaking vacuum. If you cant find the reservoir or check valve under the hood, remove the wiper cowl and it will be in there. I know for sure it is on a 95 model. Please don't forget to click on accept so i receive credit.
Thanks for asking!
Look to the left of the trans dipstick. I think it tee's into the vac line.
Click HERE for some info i found for you.
If you have further questions feel free to reply.
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