A thought and a few questions.
Typically, the R/S system is looking for a ground from the Hood Pin to disable the remote
start function. This type of hood input is called (-) N.O. and the most common. It is used
with the Viper kit supplied hood pin. With the Viper you can change the programming to
look for a open or lack of a ground in the case of a vehicle with a (-) N.C. type alarm system
( usually Fords ). See Menu 1 Feature 11. So, with default Viper programming, if you
manually ground the Hood Pin input, you have told the Viper that the hood is open and
disabled the R/S function.
Questions :
1. What year RAV4?
2. Was a bypass module used?
3. Did you install the Viper kit supplied Hood Pin?
4. How long has the system been installed?
On some newer RAV4's you can use a bypass module that will obtain the Factory installed
hood pin info from the CAN bus if the RAV4 came with the Factory Alarm system and
has a factory installed hood pin. Hence questions 2 and 3.
If you used the Viper kit supplied hood pin, question 4 comes into play. That type of hood
pin will get rusty and go bad. Typically they get stuck in the hood closed position and no
longer provide a disable signal when the hood is open, not the symptoms you are having but...
There are a few things to check if you used the Viper hood pin. First would be to check
the Viper Gray Hood Pin input wire. At some point it must breach the firewall and travel
through the engine compartment to the hood pin. I always use a rubber grommet at the
firewall to protect the wire and prevent insulation chaffing. Additionally, I use small gauge
wire loom to protect the wire as it travels through the engine compartment.
Next would be the hood pin switch itself. If it looks rusty, replace it. If the Gray wire tab
connection is close to frame metal, relocate the switch.
Of course, with the symptoms you mention, it could be the Viper control module itself.
Reseat the 24 pin harness and check the Gray wires travel within the vehicle to the firewall
for any chaffing issues. Reseating that fuse could cause wire movement that would temporarily
alleviate the problem.
Most of the above assumes you installed the Vipers hood pin switch. You could re-run that Gray
wire and use a new switch. Being as the Viper is an alarm system, a mercury tilt switch would
not be a good alternative because of the hood travel needed to trigger an alarm.
A final thought would be the Vipers Chassis Ground connection. It should be with a soldered-on
ring terminal going to a clean rust and paint free chassis location. Not to a thin metal dash
support bracket, etc.
Soldering is fun!