Help with electrical problem: 1991 Montero
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Junior Member
Joined: Jul 2024
Posts: 3
Help with electrical problem: 1991 Montero
1991 (1990 build 1st gen) v6 montero 4 door automatic. I had the fuel pump replaced by a shop that is now closed so they’re no help. It runs fine now but I have no turn signals (hazards work) and the battery goes flat if I leave it sitting. It jump starts just fine. No blown fuses. Where do I start troubleshooting? Is wiring for the fuel pump in any way close to the turn signal wiring?
Senior Member
Joined: Oct 2004
Posts: 2,044
From: Washington State
Start by figuring out what draws the battery down. The method for this is pretty straight forward:
1. Diaconnrct positive battery terminal and connect a multimeter inline between the battery positive and the wire you've disconnected.
2. Switch multimeter to Amp measuring mode and note if you're getting excessive power draw. With everything off, the normal draw should be around 0.01-0.05 Amp. If you're getting something bigger (0.5-1 Amp) you have excessive draw.
3. Pull fuses one at a time and see if removing one of them will significantly reduce power draw. You can start under the hood, then do the ones in the cabin. Make sure you tape the door switch so it "thinks" the door is closed and not turn on the cabin lights.
4. Once you isolate which sircuit has excessive draw, check which components are run by that circuit. There are usually several. Unplug each component one at a time and see if removing it from the circuit reduces the draw.
I had to go though this process on one of my "new to me" cars, because it kept drawing down the battery. In the end it turned out to be a fuel pump rely that was wired I correctly. The pump was to run though the relay coil instead of though the switched part of relay.
1. Diaconnrct positive battery terminal and connect a multimeter inline between the battery positive and the wire you've disconnected.
2. Switch multimeter to Amp measuring mode and note if you're getting excessive power draw. With everything off, the normal draw should be around 0.01-0.05 Amp. If you're getting something bigger (0.5-1 Amp) you have excessive draw.
3. Pull fuses one at a time and see if removing one of them will significantly reduce power draw. You can start under the hood, then do the ones in the cabin. Make sure you tape the door switch so it "thinks" the door is closed and not turn on the cabin lights.
4. Once you isolate which sircuit has excessive draw, check which components are run by that circuit. There are usually several. Unplug each component one at a time and see if removing it from the circuit reduces the draw.
I had to go though this process on one of my "new to me" cars, because it kept drawing down the battery. In the end it turned out to be a fuel pump rely that was wired I correctly. The pump was to run though the relay coil instead of though the switched part of relay.
Junior Member
Joined: May 2023
Posts: 9
After you diagnose the battery being bad or not, check the alternator. Hazard switch is usually the cause of your turn signal issue. They all go through the hazard switch. Hazard switches are no longer available so you will probably have to carefully take your apart and clean it. Be very careful though, they are tender at this age. Look in Facebook market place for a parts rig and see if you can find on otherwise. And no, fuel pump wiring is not close to turn signal wiring
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Apr 10, 2013 05:03 PM