I have a '94 Honda Accord that emits an unidentifiable smell when the fan is turned on. Have been to two mechanics–but they couldn’t identify the problem. I think the smell is toxic–feel like I’m going to faint when the fan is on.
Has anyone cleaned out the area under the grill right in front of the windscreen? Has anyone checked the drains from that area to make sure it is working as designed?
After checking the above, you may want to spray some Lysol or a like product designed just for this use in cars. But first make sure that area is clean of leaves etc. and the drain is not blocked.
This has happened to me a number of times. You have a dead mouse in the ventilation system. The only cure is to disassemble the airbox so that it can be removed.
Check Your Owner’s Manual. See If You’ve Got A Cabin Air Filter Or Not. If So Look At It, Smell It, And Then Change That First.
CSA
Try a detail shop. They will have experience both identifying odd smells and getting rid of them.