Bypassing the clutch switch

[max76]

Hi guys...after bypass the clutch switch is better change the starter enable relay?
how i can check if it's good or not?
Thanks in advance!!!
Max

[Paul Workman]

In ALL ZR-1s the clutch relay carries all the current drawn by the starter solenoid - a few amps. However, only on the 90-92s does the clutch switch carry the entire current to operate the starter solenoid. On the 93-95s the clutch switch enables the clutch relay (via the CCM), thus reducing the amperage load and the arching that erodes the clutch switch contact points (only) significantly.

So, it might be a good idea to have a clutch start relay (and possibly some others too) in the glove box, along with an assortment of fuses too, just in case.

90-92 Clutch schematic(1)



93-95 Clutch scematic(1)




On this topic, Scottfab pointed out that arching can be reduced in the clutch switch IF the clutch is fully engaged before, during, and after the starter is engaged vs. turning the switch to START and then engaging the clutch switch...especially on a 90-92 car.

Although the clutch switch is redundant to those of us taught to engage the clutch first any time the starter is engaged, I think it is important to have it in working order as a hedge against the unexpected - who knows what!?

Essentially converting the clutch switch to the role played by the 93-95 cars is accomplished in a 90-92 car by installing a relay between the clutch switch and the starter solenoid. This way the relatively large solenoid current is isolated from both the start relay and the clutch switch - truly a mod worth considering to improve reliability of both the clutch relay (all cars) and the clutch switch in 90-92 cars.



Locating this relay near the fused link post (under the battery) provides a convenient location to access battery power for the starter solenoid path through the new relay. And, installing its own socket for the new relay allows for quick replacement, should it be needed.

Paul
___________

ref:
(1) Marc Haibeck article posted in HOTB.

[max76]

Hi Paul...thanks for picture's!!!
I have bypassed the clutch switch and the VATS.
What can i do to resolve the problem?
Ok, i'll change the starter enable relay, there are other relays need to be change?
I also understand the car need an other relays (clutch start relay), but i don't understand how to connect it....
Thanks in advance
Max

[Dynomite]

Originally Posted by Paul Workman

Locating this relay near the fused link post (under the battery) provides a convenient location to access battery power for the starter solenoid path through the new relay. And, installing its own socket for the new relay allows for quick replacement, should it be needed.

Paul
___________

ref:
(1) Marc Haibeck article posted in HOTB.

On the Early 1990s the wire to cut is RED (there is no 12 gauge purple wire)

Starter Relay, Wiring Harness, and Plugs Tricks

I locate the Relay UNDER the ECM which is right next to the wire harness/wire to be cut.

60 / 80 AMP RELAY SPDT SINGLE POLE DOUBLE THROW NEW 654
Installed under ECM and in slot between brake booster and fire wall (perfect place for location of Relay).

Wiring modified a bit to assure Pin #87a is not hot at any time.
Pin #30: Purple wire to starter (use 3/8 inch connector on relay).
Pin #87: Red wire battery positive 12v use 3/8 inch connector on relay (connected to battery positive multiple connection post).
Pin #86: Battery ground (1/4 inch connector on relay connected to ground where battery 12 gauge wire grounded).
Pin #85: Purple wire from ECM use 1/4 inch connector on relay (Red wire on early 1990 ZR-1).
Pin #87a: Not hot at any time and not used.



Insert a short 1/2 inch long section of plastic hose
over the center connector on the Relay which is NOT
used in this application.

[Paul Workman]

Thanks, Cliff for that added info.

[max76]

Dynomite, under the driver side panel i used purple wire to bypass clutch switch...and the purple wire go to the starter...
So, in your picture there is the clutch pedal switch, i haven't that anymore, i can do it anyway?

[Dynomite]

Originally Posted by max76

Dynomite, under the driver side panel i used purple wire to bypass clutch switch...and the purple wire go to the starter...
So, in your picture there is the clutch pedal switch, i haven't that anymore, i can do it anyway?

For installation of the relay next to the Wire Harness under the ECM....cut the Purple wire in the harness (leaving a lengh of purple wire going to starter) and add a short length to the end of that purple wire coming from the ECM. That wire then connects to the 1/4 inch connector on the Relay......The center connector on that relay is NOT used.

The other end of the purple wire going to starter you connect to the Relay with a 3/8 inch connector.

But not to worry....I am going out in an hour to redo my Relay (I want to use my new heat gun on that purple wire splice shrink tube which heat gun I did not have the other day). I will take photos of the whole installation for you showing the connectors. Just hang in there

I have this same modification on three 1990s and one 1991 and they ALL function perfectly.

[max76]

DYNOMITE:


Wiring modified a bit to assure Pin #87a is not hot at any time.

Pin #30: Purple wire to starter (use 3/8 inch connector on relay).
This is the purple wire to the starter

Pin #87: Red wire battery positive 12v use 3/8 inch connector on relay (connected to battery positive multiple connection post).
There is a place where find a multiple connection? where is located?

Pin #86: Battery ground (1/4 inch connector on relay connected to ground where battery 12 gauge wire grounded).

Pin #85: Purple wire from ECM use 1/4 inch connector on relay (Red wire on early 1990 ZR-1).
I must disconnect the red wire from the ecm and connect it to pin #85?

Pin #87a: Not hot at any time and not used.

[max76]

Originally Posted by Dynomite

For installation of the relay next to the Wire Harness under the ECM....cut the Purple wire in the harness (leaving a lengh of purple wire going to starter) and add a short length to the end of that purple wire coming from the ECM. That wire then connects to the 1/4 inch connector on the Relay......The center connector on that relay is NOT used.

The other end of the purple wire going to starter you connect to the Relay with a 3/8 inch connector.

But not to worry....I am going out in an hour to redo my Relay (I want to use my new heat gun on that purple wire splice shrink tube which heat gun I did not have the other day). I will take photos of the whole installation for you showing the connectors. Just hang in there

I have this same modification on three 1990s and one 1991 and they ALL function perfectly.

Thank you so much!!!!!!

[max76]

Dynomite,
when i put the new relay the old one still works?