Fixed my 4+3
Thread Starter
Instructor
Joined: Jul 2000
Posts: 109
Likes: 0
From: Davison, Mi. 48423 USA
On a recent trip to Niagara Falls mt overdrive decided to turn itself off and on at highway speed when it wanted to. I get home and get mt shop manual out to find the problem. Checked for trouble codes, none. Checked the oil (just changed 2 months ago) full. Done all the things it said to do and the problem turned out to be the overdrive relay on the firewall. Went to the local Auto Zone bought a new on for less than 12 bucks and it works perfectly again. Just had to tell someone I'm so happy I didn't have to spend 2 grand to get this fixed. I seen some of the stories on the forum and couldn't help but think the worse all the way home. Life is good!
Team Owner
Joined: Mar 2000
Posts: 83,383
Likes: 87
From: Boston, MA
Hm... probably should replace mine also for the heck of it.
Only on hot days, my OD won't come on until the temps get up to around 185 degrees instead of the stock 118 or whatever it is. Once it engages the first time though, it's perfectly normal for the rest of the drive.
Only on hot days, my OD won't come on until the temps get up to around 185 degrees instead of the stock 118 or whatever it is. Once it engages the first time though, it's perfectly normal for the rest of the drive.
Pro
Joined: Jul 2001
Posts: 595
Likes: 9
Which one is the OD relay? Is it one of the two behing the battery? I have a 4+3 in my 88' Z51 and I am trying to locate it. Tried a new relay on both of them and it didn't solve my problem, so I was thinking that it is somewhere else???
Instructor
Joined: Mar 2000
Posts: 161
Likes: 0
The two behind the battery are the MAF relays. The OD relay is on the fire wall between the brake booster and the wiper motor. On my 87, the OD and Fuel Pump relays are on the same bracket.
Originally Posted by mooncricket
Which one is the OD relay? Is it one of the two behing the battery? I have a 4+3 in my 88' Z51 and I am trying to locate it. Tried a new relay on both of them and it didn't solve my problem, so I was thinking that it is somewhere else???
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Pro
Joined: Jul 2001
Posts: 595
Likes: 9
Originally Posted by Eric Fraser
The two behind the battery are the MAF relays. The OD relay is on the fire wall between the brake booster and the wiper motor. On my 87, the OD and Fuel Pump relays are on the same bracket.
Not there. I have been checking this out with 85vet (Forum member). He has the same set up behind the fuel pump relay, but it's not there on mine, I swear. The kicker is that my 88' GM service manual shows a diagram with it there....
If anybody out there has an 88' 4+3, could they please check it out? Would appreciate it...
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Not there. I have been checking this out with 85vet (Forum member). He has the same set up behind the fuel pump relay, but it's not there on mine, I swear. The kicker is that my 88' GM service manual shows a diagram with it there....
If anybody out there has an 88' 4+3, could they please check it out? Would appreciate it...
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