Baddabing

Car wont start now, after some projects.

Dash light up - with key on.
First thought it was the VATS system - so made a bypass.
No start.
Battery OK.
Car starts and runs when I jump the starter - so starter OK.
Bypassed the starter relay behind the DIC panel.
Still no start.
No security light.
Also bypassed the clutch switch.

Any ideas ?

s carter

With all the bypassing and jumping you have done have you looked at the Basics, Crank Fuse, Fusible links, or if the Request to turn the starter is even being made all the way back to the Ignition switch at the base of the Steering Column

Baddabing

No Basics yet :-)

Where is the crank fuse ?
Didnt know about Fusible links related to starting the car.
Have not tested the ignition switch - normally it dies slowly (tried that in my C5).

s carter

The crank fuse should be in the Fuse box Passenger side if memory serves correct L side of panel 1/2 way down next to LCD fuse

One very helpful Thing to have and I am sure this is no Big Surprise is a True FSM not a hays/Chiltons for your Year, Worth the Extra Dollars for the Factory books

Baddabing

Just checked all fuses in the fuse box - all ok.
Checked Fusible links - all ok.

Can the VATS module go bad ?
Ignition switch on a C4 - is there a simple test procedure ?

s carter

probably but all can relate is find a Circuit Diagram (Which I don't Have)
I'm running off 30 year old memory's is back probe the terminals once you Know what color wire goes with the crank request down on the column Long Flat Connector and make sure the plug is good now it's all part of the Basics,

Hooked on Vettes

When you turn the ignition switch to Start you should hear the starter enable relay behind the driver info center click.

If it does that tells you the Pass Key Decoder Module is grounding the starter enable relay and 12 volts should pass thru the relay to the Clutch Safety switch.

The 12 volts passes thru the Clutch Safety switch on a Purple wire to the Starter solenoid.

If the Starter Solenoid clicks but the Starter motor doesn't spin that usually indicates the copper contact on the Starter Solenoid plunger that makes contact with the copper contacts connected to the starter motor windings are pitted and need to be replaced.

Baddabing

Thanks for helping.

There was a click behind the dash - before I bypassed the relay, and the Clutch Safety switch is also bypassed, so the solution is a new starter ?

Hooked on Vettes

You need to verify there is 12 volts at the Starter motor lug.

There is a direct connection from the positive battery terminal to the starter motor lug. It's HOT all the time.

The Purple wire at the Starter solenoid lug should have 12 volts on it when the ignition switch is in Start.

There is also a fusible link at the Starter motor terminal lug which is used for the Blower motor module. That is not your problem.

For safety reasons, make sure you remove the bypass jumper you installed on the Clutch Safety Switch. You don't want the starter to engage unless the Clutch pedal is depressed.

You said you jumped the Stater motor and it worked so it could be bad wiring connections at the Starter. The only way to verify is by measuring the voltage at each wire.

Also verify the ground wire from the negative battery terminal to the engine block is clean.

The video below explains how the copper contacts in the Nippondenso starter work. Usually if the copper contacts are bad you will hear a loud click at the Starter motor but the Starter doesn't spin.

http://www.nationsautoelectric.com/densoparts.html