C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

84 won't start/theft module

Thread Tools
 
Search this Thread
 
Old Apr 6, 2006 | 12:00 PM
  #1  
jvesalga's Avatar
jvesalga
Thread Starter
Racer
10 Year Member
 
Joined: Jan 2002
Posts: 330
Likes: 0
From: Simi Valley ca
Default 84 won't start/theft module

This morning I am having trouble with starting my 84. When I key the ignition it seems to be activating the theft detterant module immediately. I finally got it to start drove to work and it is doing the same.

If I disconnect the module will the car start? Also does anyone know where it is located? I am at work now and my manual is at home.

thanks

joe
Reply
Old Apr 6, 2006 | 12:31 PM
  #2  
qws's Avatar
qws
Melting Slicks
10 Year Member
 
Joined: Jan 2005
Posts: 2,658
Likes: 4
From: Clifton Park NY
Default

I think its above the transmission. I don't have my FSM manual near me so I can't be totally accurate. This is an assumption on my part. My module on my 84 is not connected and it still runs. I recommend getting the fsm for the car it does help in troubleshooting.
Reply
Old Apr 6, 2006 | 02:09 PM
  #3  
rons85's Avatar
rons85
Burning Brakes
 
Joined: Apr 2004
Posts: 762
Likes: 2
From: Huntington ma
Default

On an '85 (should be the same) the Anti theft/starter interrupt module is behind the center of the dash. Are you Sure that's what's happening - if the alarm is "on" then it won't crank - the starter solenoid is interrupted. To "clear" or "disarm" the alarm you use the door key to unlock Either door. This assumes that the contact set in the door at the key tumbler (either one) is still functioning... Key in the ignition switch will NOT disarm the alarm.
Reply
Old Apr 6, 2006 | 04:46 PM
  #4  
jvesalga's Avatar
jvesalga
Thread Starter
Racer
10 Year Member
 
Joined: Jan 2002
Posts: 330
Likes: 0
From: Simi Valley ca
Default

Thank you both for the reply, now off to find a screwdriver.

joe
Reply
Old Apr 7, 2006 | 01:32 AM
  #5  
CentralCoaster's Avatar
CentralCoaster
Team Owner
 
Joined: May 2002
Posts: 24,337
Likes: 25
From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
Default

The Theft deterrent module is located behind the passenger dash pad, it's mounted just forward of the ecm, at a 45 degree angle. There's a 17pin connector that unplugging will disable it.

Pulling the horn fuse will kill power to it too, this is hidden behind the center dash selector switches, probably a 10 amp fuse.

The starter disable relay is back there too, it's mounted sideways on the right side. The other sideways mounted piece is the door lock relay.

If your door lock switch is bad, the alarm will not disarm. Someone may have hacked the system up instead of fixing the door switch. Try the passenger side door.

Last edited by CentralCoaster; Apr 7, 2006 at 01:37 AM.
Reply
Old Apr 7, 2006 | 11:31 AM
  #6  
jvesalga's Avatar
jvesalga
Thread Starter
Racer
10 Year Member
 
Joined: Jan 2002
Posts: 330
Likes: 0
From: Simi Valley ca
Default

Thanks for the info on the location, I took a look and did not see a module at a 45 degree angle, I also found a diagram on the net of what you described. I can't find the 17 pin relay, I found a 5 pin relay and removed it and it disabled the starter. Plugged it back in and it startered. So while the car was running I unplugged it shut the engine off and was able to to get to start. But now I still have the same problem, so I will have to take another look for the 17 pin relay.

thanks

joe
Reply
Old Apr 8, 2006 | 12:49 AM
  #7  
mstock's Avatar
mstock
Instructor
 
Joined: Jan 2005
Posts: 146
Likes: 0
Default If it is a 84 all you have to do is...

Take off the cluster in the middle of your dash(one with all the switches). Behind that you will find a fuse. Remove the fuse and the theft system in now non-functional.
Reply
Old Apr 8, 2006 | 08:57 AM
  #8  
Brimis's Avatar
Brimis
Drifting
20 Year Member
Liked
Loved
Community Favorite
 
Joined: May 2003
Posts: 1,647
Likes: 28
From: Woodbridge NJ
Default

Originally Posted by jvesalga
Thanks for the info on the location, I took a look and did not see a module at a 45 degree angle, I also found a diagram on the net of what you described. I can't find the 17 pin relay, I found a 5 pin relay and removed it and it disabled the starter. Plugged it back in and it startered. So while the car was running I unplugged it shut the engine off and was able to to get to start. But now I still have the same problem, so I will have to take another look for the 17 pin relay.

thanks

joe

Looking at my manual I see the theft deterrent module is located behind the dash pad.
Reply
Corvette Stories

The Best of Corvette for Corvette Enthusiasts

story-0

10 Ugly Corvettes That We Still Kinda Love

 Joe Kucinski
story-1

Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer

 Brett Foote
story-2

10 Things Every Corvette Owner Needs (2026 Edition)

 Michael S. Palmer
story-3

8 Most "Only Corvette Owners Understand" Quirks and Problems

 Pouria Savadkouei
story-4

10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years

 Joe Kucinski
story-5

How Much Horsepower Every Corvette Engine "LOST" in 1972

 Joe Kucinski
story-6

Top 10 DOs and DON'Ts for Protecting Your Convertible Top!

 Michael S. Palmer
story-7

Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!

 Joe Kucinski
story-8

150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter

 Joe Kucinski
story-9

8 Coolest Corvette Pace Cars (and Replicas) of All Time

 Verdad Gallardo
Old Apr 8, 2006 | 10:32 AM
  #9  
mstock's Avatar
mstock
Instructor
 
Joined: Jan 2005
Posts: 146
Likes: 0
Default unless you are planning to replace the module

Unless you plan on replacing it, all you really need to do is remove the fuse behinf the middle cluster. It is easier than removing all the other stuff. I know thisbecause I've been there...done that
Reply
Old Apr 8, 2006 | 05:32 PM
  #10  
jvesalga's Avatar
jvesalga
Thread Starter
Racer
10 Year Member
 
Joined: Jan 2002
Posts: 330
Likes: 0
From: Simi Valley ca
Default

Thanks I found it, I can get my hand on it and pull back the interlock tab, but it is stuck. Really stuck. It feels like some of the pins are frozen to the relay. The relay is held on by one bolt, I am prying so hard, even if it breaks the relay tab don't care. The good news is all the moving around lets the car start. When it triggers I can simply move it a bit and it resets.

thanks

joe
Reply

Get notified of new replies

To 84 won't start/theft module





All times are GMT -4. The time now is 06:16 PM.

story-0
10 Ugly Corvettes That We Still Kinda Love

Slideshow: 10 ugly Corvettes that we still kinda love.

By Joe Kucinski | 2026-06-03 10:34:17


VIEW MORE
story-1
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer

A lot of money has changed hands at the online auction house over the years.

By Brett Foote | 2026-06-03 10:21:50


VIEW MORE
story-2
10 Things Every Corvette Owner Needs (2026 Edition)

Slideshow: 10 great gifts Corvette enthusiasts actually want for Father's Day!

By Michael S. Palmer | 2026-06-03 15:43:40


VIEW MORE
story-3
8 Most "Only Corvette Owners Understand" Quirks and Problems

Slideshow: These are the quirks, annoyances, and oddly lovable problems that every Corvette owner eventually learns to live with.

By Pouria Savadkouei | 2026-05-28 09:31:39


VIEW MORE
story-4
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years

Slideshow: 10 reasons why the C6 Z06 is still a performance benchmark after 20 years.

By Joe Kucinski | 2026-05-27 17:20:09


VIEW MORE
story-5
How Much Horsepower Every Corvette Engine "LOST" in 1972

Slideshow: How much horsepower every Corvette engine lost in 1972.

By Joe Kucinski | 2026-05-27 16:54:53


VIEW MORE
story-6
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!

Slideshow: How to Protect A Convertible Top: 10 DOs & DON'Ts

By Michael S. Palmer | 2026-04-03 00:00:00


VIEW MORE
story-7
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!

Slideshow: The 10 most explosive Corvettes ever built based on power-to-weight ratio.

By Joe Kucinski | 2026-05-20 07:23:03


VIEW MORE
story-8
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter

Slideshow: From C1 to C8 we compare every Corvette generation by the numbers.

By Joe Kucinski | 2026-05-12 16:54:12


VIEW MORE
story-9
8 Coolest Corvette Pace Cars (and Replicas) of All Time

Slideshow: Some Corvette pace cars became collectible legends, while others perfectly captured the look and attitude of their era.

By Verdad Gallardo | 2026-05-11 09:50:51


VIEW MORE