A/C wiring connections

1995 PEUGEOT 406
327,999 MILES • 2.0L
Avatar
HASSAN SHUAIBU
  • MEMBER
  • 40 POSTS
My engine rpm drops to 550 when on AC.
Mar 29, 2019 at 1:29 PM
Advertisement
Avatar
JOETECHPRO
  • CERTIFIED EXPERT
  • 705 POSTS
Hey HASSAN SHUAIBU,

Does the same thing happen when you turn electrical loads on?

Does the A/C work?

Turn on all electric items eg. headlights, rear window defogger, wipers.

If this load does not affect the idle then you may have an issue with the the A/C compressor.

How is the idle generally?
Stable and smooth?

A good place to start would be to clean the throttle body on your vehicle. Guide below:

https://www.2carpros.com/articles/throttle-actuator-service

Also check for vacuum leaks:

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

I do not have the specifics for your vehicle but i would also advise checking your idle control valve and cleaning if necessary.

You may be able to find a guide for this online.

If you post some pictures we should be able to identify the items you need to remove/clean.

Regards, Joe
Mar 29, 2019 at 5:39 PM
Avatar
HASSAN SHUAIBU
  • MEMBER
  • 40 POSTS
Yes sir, the AC works fine and it's only the AC that cause the drop in rpm. I assume when AC is switched on the rpm suppose to increase to compensate for the load increase. Though I usually see check engine like when at idle but the moment I start to accelerate the light will disappear. Also when I depress the throttle at idle the light disappears.
Mar 29, 2019 at 10:05 PM
Advertisement
Avatar
JOETECHPRO
  • CERTIFIED EXPERT
  • 705 POSTS
Hey HASSAN SHUAIBU,

If you can follow the guide below and scan for codes that will be helpful in getting this fixed:

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

It sounds like your idle control is not working.

The guides from before for cleaning throttle and checking for vacuum leaks may find the problem but it will be quicker if you get the codes.

Hope that helps.

Regards, Joe
Mar 29, 2019 at 10:53 PM