Lt1/ZF6 Swap into early C4 Problem solving thread
Thread Starter
Racer
Joined: May 2009
Posts: 256
Likes: 0
Lt1/ZF6 Swap into early C4 Problem solving thread
I've been tinkering with this project for some time now and I've been blasting numerous threads on here. So to save threads and for convenience of me not spamming the wall, I'm gonna make this one to address any issues on my project car.
For those that don't know I have swapped out the L98 and the Auto Trans of my 87 vert with a 95 LT1 with the ZF6. Other things have been done like the rear end with 3.55 gear ratio, Polyester bushings, ball joints.
The PCM came with the engine and trans and was tuned to disable VATS and 1st/4th gear solenoid.
Once I clean things up a bit I'll get some pics up!
//////////////////////////////////////////////////////////////////////////////////
Heres my current problem Im tackling.
We cut alot of wires out of the engine bay and connected the new harness.
We somehow cut power from the blower motor/radio.
Right now id like to get the blower motor working because when it rains, it gets quite foggy on the windshield.
I tested the blower motor with straight 12v power.... it works!
But no voltage from the connecter with ignition on, motor on high.
Before the swap, blower motor only worked on high... which I've read is a resistor issue. Just getting one speed working would be a win here.
I no longer have the old ECM connected. Would this alone disable the climate control and blower motor???
I dont believe power is going to the old ECM connector. A friend did most of wiring and I dont know if it would even be grounded either.
Fuses are not blown but fuse links by the battery have been altered so also could be issue.
For those that don't know I have swapped out the L98 and the Auto Trans of my 87 vert with a 95 LT1 with the ZF6. Other things have been done like the rear end with 3.55 gear ratio, Polyester bushings, ball joints.
The PCM came with the engine and trans and was tuned to disable VATS and 1st/4th gear solenoid.
Once I clean things up a bit I'll get some pics up!
//////////////////////////////////////////////////////////////////////////////////
Heres my current problem Im tackling.
We cut alot of wires out of the engine bay and connected the new harness.
We somehow cut power from the blower motor/radio.
Right now id like to get the blower motor working because when it rains, it gets quite foggy on the windshield.
I tested the blower motor with straight 12v power.... it works!
But no voltage from the connecter with ignition on, motor on high.
Before the swap, blower motor only worked on high... which I've read is a resistor issue. Just getting one speed working would be a win here.
I no longer have the old ECM connected. Would this alone disable the climate control and blower motor???
I dont believe power is going to the old ECM connector. A friend did most of wiring and I dont know if it would even be grounded either.
Fuses are not blown but fuse links by the battery have been altered so also could be issue.
Melting Slicks
Joined: Aug 1999
Posts: 2,240
Likes: 42
From: Baltimore, MD USA
For the Blower motor to work.
You need 12 volts from the AC fuse which is hot when the
ignition switch is On.
That 12 volts goes to a Brown wire at the HVAC control head.
You also need 12 volts from a Red wire at the starter motor.
The starter motor has a cable from the battery connected to it.
At the same terminal lug at the starter motor is a Red fusible
link wire that goes to the Blower Motor and is hot all the time.
To verify that Red wire is connected at the starter motor
you should measure 12 volts on the Red wire at the Blower
Motor relay socket.
Since you swapped motors, that wire could have been
removed or left hanging at the starter motor.
You need 12 volts from the AC fuse which is hot when the
ignition switch is On.
That 12 volts goes to a Brown wire at the HVAC control head.
You also need 12 volts from a Red wire at the starter motor.
The starter motor has a cable from the battery connected to it.
At the same terminal lug at the starter motor is a Red fusible
link wire that goes to the Blower Motor and is hot all the time.
To verify that Red wire is connected at the starter motor
you should measure 12 volts on the Red wire at the Blower
Motor relay socket.
Since you swapped motors, that wire could have been
removed or left hanging at the starter motor.
Thread Starter
Racer
Joined: May 2009
Posts: 256
Likes: 0
Ok worked at this all night and morning. Found the Red wire and traced it back into the loom. It was cut off. Connected a wire to it and attached it to the starter.... and it works!
Like before I said it only works on high setting, which is still true. I tried running throung the hand book and did the tests with the multimeter.
I ohm tested the resistors. They were all over the spec but not by that much and were all relatively correct to each other. One was over .4 ohms, other were of by couple ohms. Can that really stop it from working all together?
Also ohm tested the relay connecter. It supposed to read zero ohms which it did, but then shot up to 128 after couple seconds. These wires from the connector looked fine though So I doubt it is that.
What is a way to test the blower motor switch?
Like before I said it only works on high setting, which is still true. I tried running throung the hand book and did the tests with the multimeter.
I ohm tested the resistors. They were all over the spec but not by that much and were all relatively correct to each other. One was over .4 ohms, other were of by couple ohms. Can that really stop it from working all together?
Also ohm tested the relay connecter. It supposed to read zero ohms which it did, but then shot up to 128 after couple seconds. These wires from the connector looked fine though So I doubt it is that.
What is a way to test the blower motor switch?
Melting Slicks
Joined: Aug 1999
Posts: 2,240
Likes: 42
From: Baltimore, MD USA
There are four blower speeds.
At the Blower Resistor connector.
Lo blower speed is a Yellow wire
M1 blower speed is a Tan wire
M2 blower speed is a Light Blue wire
Dark Blue wire is the output voltage from the Blower
Resistors and powers the Blower Motor thru the
normally closed contacts of the Blower Motor relay.
With the connector at the Blower Resistor disconnected.
On the connector, jump the Light Blue wire to the Dark Blue wire.
Set Blower speed to M2.
Turn the ignition On.
If the Blower motor runs, the Blower resistor is bad.
If the blower motor doesn't run verify there is 12 volts
on the Light Blue wire.
If no 12 volts on the Light Blue wire the M2 contacts of
the Blower switch are bad.
If you have 12 volts on the Light Blue wire and the
Light Blue wire is jumped to the Dark Blue wire and
the Blower motor doesn't run, the Blower Motor relay
is bad.
To eliminate the Blower Motor relay, remove the relay from its socket.
At the socket use a piece of wire and jump the Dark Blue
to the Black/Red wire.
At the Blower Resistor connector.
Lo blower speed is a Yellow wire
M1 blower speed is a Tan wire
M2 blower speed is a Light Blue wire
Dark Blue wire is the output voltage from the Blower
Resistors and powers the Blower Motor thru the
normally closed contacts of the Blower Motor relay.
With the connector at the Blower Resistor disconnected.
On the connector, jump the Light Blue wire to the Dark Blue wire.
Set Blower speed to M2.
Turn the ignition On.
If the Blower motor runs, the Blower resistor is bad.
If the blower motor doesn't run verify there is 12 volts
on the Light Blue wire.
If no 12 volts on the Light Blue wire the M2 contacts of
the Blower switch are bad.
If you have 12 volts on the Light Blue wire and the
Light Blue wire is jumped to the Dark Blue wire and
the Blower motor doesn't run, the Blower Motor relay
is bad.
To eliminate the Blower Motor relay, remove the relay from its socket.
At the socket use a piece of wire and jump the Dark Blue
to the Black/Red wire.
Thread Starter
Racer
Joined: May 2009
Posts: 256
Likes: 0
There are four blower speeds.
At the Blower Resistor connector.
Lo blower speed is a Yellow wire
M1 blower speed is a Tan wire
M2 blower speed is a Light Blue wire
Dark Blue wire is the output voltage from the Blower
Resistors and powers the Blower Motor thru the
normally closed contacts of the Blower Motor relay.
With the connector at the Blower Resistor disconnected.
On the connector, jump the Light Blue wire to the Dark Blue wire.
Set Blower speed to M2.
Turn the ignition On.
If the Blower motor runs, the Blower resistor is bad.
If the blower motor doesn't run verify there is 12 volts
on the Light Blue wire.
If no 12 volts on the Light Blue wire the M2 contacts of
the Blower switch are bad.
If you have 12 volts on the Light Blue wire and the
Light Blue wire is jumped to the Dark Blue wire and
the Blower motor doesn't run, the Blower Motor relay
is bad.
To eliminate the Blower Motor relay, remove the relay from its socket.
At the socket use a piece of wire and jump the Dark Blue
to the Black/Red wire.
At the Blower Resistor connector.
Lo blower speed is a Yellow wire
M1 blower speed is a Tan wire
M2 blower speed is a Light Blue wire
Dark Blue wire is the output voltage from the Blower
Resistors and powers the Blower Motor thru the
normally closed contacts of the Blower Motor relay.
With the connector at the Blower Resistor disconnected.
On the connector, jump the Light Blue wire to the Dark Blue wire.
Set Blower speed to M2.
Turn the ignition On.
If the Blower motor runs, the Blower resistor is bad.
If the blower motor doesn't run verify there is 12 volts
on the Light Blue wire.
If no 12 volts on the Light Blue wire the M2 contacts of
the Blower switch are bad.
If you have 12 volts on the Light Blue wire and the
Light Blue wire is jumped to the Dark Blue wire and
the Blower motor doesn't run, the Blower Motor relay
is bad.
To eliminate the Blower Motor relay, remove the relay from its socket.
At the socket use a piece of wire and jump the Dark Blue
to the Black/Red wire.
You've helped me again. Thanks for making this so easy! It's the relay! Getting stuff done I love it!
Also looked into my radio which is not powering on. Its an aftermarket head unit. Traced the wires in schematic to see what wires correlate with the aftermarket wiring harness. It is receiving 12volt power all the way to the end of the aftermarket wiring harness which leads me to believe my head unit has died. Looking for replacement.
///////////////////////////////////////
Things left to do.
-Address slight low idle problem (may be IAC)
-Fiberglass hole around stick shift
-Replace cracked windshield
-Reinstall interior dash
-Fix fusible link behind battery pulling 4amp charge with car off.(Temp fixed with relay)
Thread Starter
Racer
Joined: May 2009
Posts: 256
Likes: 0
Knocked two things out of the way today.
Actually 3!
Got new blower motor relay. Installed and blower motor is now fully functional!
Radio I had was actually not dead but had a disconnected wire in the harness. It hooked up and plays music!
Most importantly got my VSS working! Forgot to list it as a thing to do I see..... Finally have speedometer displaying( I've been staring at a zero forever). Used the Dakota Digital interface which worked out great. This may have also fixed my low idle. I'm gonna see if it acts up again with a few more drives.
///////////////////////////////////
Things to do:
-Fiberglass hole around stick shift
-Replace cracked windshield
-Reinstall interior dash
-Fix fusible link behind battery pulling 4amp charge with car off.(Temp fixed with relay)
BTW What is this box above the electronic spark control module?
AND HERE IS SOME EYE CANDY!
Actually 3!
Got new blower motor relay. Installed and blower motor is now fully functional!
Radio I had was actually not dead but had a disconnected wire in the harness. It hooked up and plays music!
Most importantly got my VSS working! Forgot to list it as a thing to do I see..... Finally have speedometer displaying( I've been staring at a zero forever). Used the Dakota Digital interface which worked out great. This may have also fixed my low idle. I'm gonna see if it acts up again with a few more drives.
///////////////////////////////////
Things to do:
-Fiberglass hole around stick shift
-Replace cracked windshield
-Reinstall interior dash
-Fix fusible link behind battery pulling 4amp charge with car off.(Temp fixed with relay)
BTW What is this box above the electronic spark control module?
AND HERE IS SOME EYE CANDY!
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Thread Starter
Racer
Joined: May 2009
Posts: 256
Likes: 0
Came up with an issue recently though.
Here in Nothern IL it has been really hot. 100 degrees plus humid weather. When it is extremely hot out, I've noticed my interior lights will stay on with the car off and door shut. Drive it home at night when its cooler, and they go off.
So get this. I drive early in the morning to work on Saturday. I watched the lights go off before leaving car.
It gets hot again mid day, and when I walk out to my car, lights are on!.
Now it has cooled off so it hasnt done it again. Could this be a failing delay module or another issue like switches?
Thread Starter
Racer
Joined: May 2009
Posts: 256
Likes: 0
Courtesy light issue hasnt returned since its been cooler out but noticed the lights do not come on when the passenger door is opened.
Gonna check the manuel for diagnosis.
Also still noticing a low idle drop when driving and lifting of the gas. Does not do it as bad as it did when I had no speedometer. Idle comes back up to 700 within a couple seconds and stays there, but it happens occasionally... I cant think of anything else but IAC.
Gonna check the manuel for diagnosis.
Also still noticing a low idle drop when driving and lifting of the gas. Does not do it as bad as it did when I had no speedometer. Idle comes back up to 700 within a couple seconds and stays there, but it happens occasionally... I cant think of anything else but IAC.
Drifting
Joined: May 2005
Posts: 1,336
Likes: 12
From: Chicago Executive Airport, formerly known as Palwaukee
No-IL Events Coordinator
St. Jude Donor '12-'13-'14-'15-'16-'17
I would check the resistance in your Throttle Position Sensor before looking at other possible causes for your idle fluctuation. This can be done with the engine off to make certain the ohms change correctly with the position of the sensor.
The TPS is prone to inaccurate calibration.
The TPS is prone to inaccurate calibration.
Thread Starter
Racer
Joined: May 2009
Posts: 256
Likes: 0
I would check the resistance in your Throttle Position Sensor before looking at other possible causes for your idle fluctuation. This can be done with the engine off to make certain the ohms change correctly with the position of the sensor.
The TPS is prone to inaccurate calibration.
The TPS is prone to inaccurate calibration.
rpms go up then come down real low to about 400-500. Sometime I even hear it knock once, then it idles normal
Thread Starter
Racer
Joined: May 2009
Posts: 256
Likes: 0
I would check the resistance in your Throttle Position Sensor before looking at other possible causes for your idle fluctuation. This can be done with the engine off to make certain the ohms change correctly with the position of the sensor.
The TPS is prone to inaccurate calibration.
The TPS is prone to inaccurate calibration.
And what color wires are what?
Thread Starter
Racer
Joined: May 2009
Posts: 256
Likes: 0
What is a scanner that will work for the 95 vette? Being that my Engine and Pcm from a 95 is in a 87 body, The paper clip trick will not work since I do not have the dash of a 95 that will display the codes. I tried to get it tested at Autozone but it would not read. Any help? I have intermittent SES light popping up.
P.S. The SES light from the 87 dash is hooked up, but will not display the codes. I tried the paperclip trick already and the fan would kick on but SES light would not do anything.
P.S. The SES light from the 87 dash is hooked up, but will not display the codes. I tried the paperclip trick already and the fan would kick on but SES light would not do anything.