There are a few possibilities;
First, let me clarify about which interior lights come on. Is it the dash lights or the interior dome and/or map lights, etc?
The flasher relay could be bad. But that leaves the question of how the interior dome light is flashing.
If it is the dome light, I would think that the alarm system or automatic entry system has an issue.
The interior light/security relay could be part of the issue.
There is also a PCU that controls the remote lock/lights and alarm. It could be faulty.
The easiest step to take next, (and to not spend any money except for about 15 or so minutes of labor), is to have the OBD, (On Board Diagnostic), codes checked for trouble codes.
Is there an aftermarket alarm system on the car?
If so, this might complicate the OBD reading or make it useless in finding the source of the problem.
Are there any issues with the flashers or dome lights otherwise?
Do the dash lights come on and go off as they should?
Let me know if this helps and if I can be of any further assistance.
Monday, August 22nd, 2011 AT 3:58 AM