a/c does not work a/c light blink whrere to start?

[jaydeep]

I have 98 corolla and AC does not work. When car is on and press AC button, compressor seems to be running for a minute then ac light start blinking.
My question is where should I start? After reading some post someone suggest swapping AC relay with horn reply.

[fishexpo101]

Before you start swapping parts - be a good idea to double check the line pressures. If there is not enough or too much refrigerant, the system will shut itself down to protect the compressor. Once you determine that the system is properly charged - then you can start debugging the electricals.

[jaydeep]

Originally Posted by fishexpo101

Before you start swapping parts - be a good idea to double check the line pressures. If there is not enough or too much refrigerant, the system will shut itself down to protect the compressor. Once you determine that the system is properly charged - then you can start debugging the electricals.

Can you tell me what pressure should be? If there is problem with pressure what should I do?

Thanks

[fishexpo101]

Pressures should be measured with manifold gauges A/C in recirc mode, engine at 2000 RPMs, max cooling.

Low-side should be between 0.15-0.25 MPa (21-36 PSI)
High-side should be between 1.37-1.55 MPa (199-225 PSI)

Most people do not have this equipment to handle this sort of diagnosing/job. I would take it to a HVAC specialist. If the refrigerant level is low - then can recharge it correctly. If the level is too high, they can evacuate the system legally.