LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

SES light need help

Old Apr 10, 2003 | 09:33 AM
  #1  
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SES light need help

I have on ODBII PCM and did the mod from the following site http://users.oco.net/xero/fanmod/. I unhooked the battery before I started and did all the yada yada per instructions. I even busted an LED and had to make a trip back to RadioShack halfway through the install but I had NO SES light at that time. I got back finished all the work with the battery hooked up (therefore I plugged in the fans and lighter while the battery was still hooked up this time (curious if this caused the SES light?), I then tested it all before I put the console back together and the Low & High fans work just like the instructions claim. So I crank her up and go for a test drive and right off the bat I have an SES. Did I do something wrong battery wise (hooking and unhooking?) Will it go away with time (like a reset from unhooking the battery?) I thought I wired something wrong but if I did the fans would not work I think. Any help is appreciated.
Old Apr 10, 2003 | 10:30 AM
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i really dont think this belongs in advanced tech, you'll get more responses in lt1 tech. but if you just tripped a code in the pcm you can clear them out by pulling the pcm bat fuse out of your dash i think its the third from the left on the top row.... you have a diagram on the panel you'll find it. i'm pretty sure its amber colored if you dont have a diagram.
Old Apr 10, 2003 | 11:03 AM
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ok thanks
Old Apr 10, 2003 | 12:56 PM
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Please post generation specific "tech" questions on the appropriate forum.... in this case "LT1 Tech". You might also want to consider using the "Computer......" forum.

Moving to LT1 Tech....
Old Apr 10, 2003 | 01:51 PM
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Originally posted by Injuneer
Please post generation specific "tech" questions on the appropriate forum.... in this case "LT1 Tech". You might also want to consider using the "Computer......" forum.

Moving to LT1 Tech....
yeah yeah ok ok thanks for the lecture
Old Apr 10, 2003 | 02:13 PM
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Be nice to the moderators. They have good memories.

I bet if you have it scanned, P1641 or P1642 will show up. OBD-II is cranky about the fans being on when the pcm does not tell them to be. Use this diagram and add the 47 ohm resistors to your wiring (don't worry about anything else on the diagram if your fans and LEDs are working like you want). I am told by others that have done it, that it works fine.
Old Apr 11, 2003 | 10:31 AM
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Originally posted by shoebox
Be nice to the moderators. They have good memories.

I bet if you have it scanned, P1641 or P1642 will show up. OBD-II is cranky about the fans being on when the pcm does not tell them to be. Use this diagram and add the 47 ohm resistors to your wiring (don't worry about anything else on the diagram if your fans and LEDs are working like you want). I am told by others that have done it, that it works fine.
hey I done just that and sure enough those were the codes. I unhooked the connections under the hood and we cleared them and no problems. You are correct about the sensitive PCM..thanks for the diagram I'm checking it out now.
Old Apr 11, 2003 | 10:40 AM
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Originally posted by shoebox
:

I bet if you have it scanned, P1641 or P1642 will show up. OBD-II is cranky about the fans being on when the pcm does not tell them to be. Use this diagram and add the 47 ohm resistors to your wiring (don't worry about anything else on the diagram if your fans and LEDs are working like you want). I am told by others that have done it, that it works fine.
I am looking at this diagram and have a couple questons? First off did you check out my link for the diagram I originally used? If so I think I used 470ohm 1/2 watt resistors between the power source and non-blinking LEDs. Now if I'm understanding this new diagram correctly I need to addiontally add (3) 1 watt 47 ohm resistors and (2) of these splice into the dark blue wire as you described and has a jumper which confuses me. What purpose does that have? Same wire and one is bridged with the same resistor. ok and of course (1) goes on the green wire. Does this have to be close to the splice under the hood or can I do it under the dash?
alternate email for me is bgt1963@hotmail.com. I want to fix this after work today so if you get this soon I appreciate it.
Old Apr 11, 2003 | 12:46 PM
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Originally posted by shoebox
:
I bet if you have it scanned, P1641 or P1642 will show up. OBD-II is cranky about the fans being on when the pcm does not tell them to be. Use this diagram and add the 47 ohm resistors to your wiring (don't worry about anything else on the diagram if your fans and LEDs are working like you want). I am told by others that have done it, that it works fine.
Shoebox you da man, it works awesome no SES and on a hot day here in Houston with MAX AC I'm running 175 consistently even at stop lights...awesome thank you sir.
Old Apr 11, 2003 | 01:36 PM
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Originally posted by Brettinator
Shoebox you da man, it works awesome no SES and on a hot day here in Houston with MAX AC I'm running 175 consistently even at stop lights...awesome thank you sir.
It's a beautiful day, here. I had to go out for a drive.

The diagram was supplied by KC Larson. He gets the credit for the resistor trick.
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