91 Previa Electrical Problem

[janeldavis]

Hi Everyone-
New here and have a new to me AWD supercharge LE Previa. I love it, but it has had some weird and frustrating problems. I got it to fit our growing family. We have a two year old and a newborn, so needless to say, we don't have a lot of time to be figuring out weird electrical problems on our new van.

Let me start at the beginning...We got our new van detailed at Car Toys, and while we were there I decided to get a remote start and remote lock/unlock. I can't tell if that was the beginning of our problems or not. Any insights???

Are friend/mechanic replaced the CV joints for us and did some other work. While the van was at his place the alarm would occasionally go off. Since this hadn't been a problem before, I thought it was because of the add on from Car Toys. We got it home, the alarm (factory alarm I think, we didn't even know it had it) went off again. Then we needed a new battery.

Now...new problem. We got a new battery. The people at O'Reilley's put it in backwards. Then the van wouldn't start! We had it towed down to Car Toys. They said it wasn't their system, their system was working fine and did a work around to "fix" the problem, by grounding the hood. So that the van thinks the hood is open and won't have the alarm go off.

Now I was driving home from daycare and my clock, speedometer, turn signals, windows, locks, weren't working. When I parked, I looked at the fuse box and the relay for "Heat" was quite hot and seemed to be the relay for the things that weren't working. I bought a new one and it didn't work. (Also, all fuses looked good.) Also, now my van wouldn't start. No sound whatsoever when I turned the key.

My husband and our mechanic figured out that it might be the fuse box attached to the battery. (name?) They pulled those in and out and then manually unlocked and locked the door and that seemed to work. The problem is though, it keeps doing the all electrical going out problem, including the ignition and we can't start it. I need a reliable van for me and the kids. Any help would be GREATLY appreciated. THANK YOU! I'm wondering if we should get the automatic lock and starter removed, is that the source of our problems?

Janel

[timsrv]

With so many things going on it can become difficult to troubleshoot. Personally I think it was a mistake to have these accessories installed (at least by Car Toys). I made the mistake of letting them install a stereo for me once and they screwed EVERYTHING up. They cut wires that shouldn't have been cut, they did poor splices (some were just twisted together & taped), they lost screws, etc. They also pried & bent some parts & broke some mounting tabs. Instead of enjoying my new stereo I became infuriated listening to all the new rattles coming from my dash. I ended up ripping it all back out, repairing their work, then putting it all back together. I went back the next day with a list of the missing screws/fasteners. It took an angry call to their manager (not there) before they would allow me access to the shop. One of the "installers" handed me a box full of bolts, screws, fasteners & misc parts (apparently from lots of cars) and said "If we have them this is where they would be". Sure enough, after a few minutes of picking through it I found everything on my list (although I'm not sure it was all from my Previa).

Sorry about the rant, but this is the type of work ethic you can expect from Car Toys & similar places. As a troubleshooter, I can't tell you how many times problems like this I've traced back to bad accessory installations. Of course the Previa is getting old so there's a good chance it's something unrelated. Since they were messing with the security system, I'm guessing the issue was created by them. In situations like this, as a troubleshooter, I would start out by going back into the areas they were working in and look for mistakes, bad connections, etc. If nothing obvious presents itself, next, as a troubleshooting measure, I would disconnect the accessory(s) and wire back to normal. It's usually pretty easy to figure out original wiring (just look for the "hack" stuff like scotch locks, cut wires, & electrical tape, remove it, then match up original wires using original color markings). If that doesn't solve the issue, at least it eliminates these things as possible faults & will make further troubleshooting easier. If the problem is found in a factory system, after the problem is resolved you can always go back and hook these items back up.

When it comes to factory security system issues, the most common problems are related to the door sensors. Here's a thread where this is discussed: http://www.toyotavantech.com/forum/s...at-on-the-dash. Good luck. Tim

[janeldavis]

Thanks Tim. I appreciate it and now know about getting a system like that put in at Car Toys. Ugh.

Do you think that security system issue would account for the weird electrical going out while driving? Or do you think that is a separate issue? I saw your security post already adn thought some of it fit our van, but not all of it.

With so many things going on it can become difficult to troubleshoot. Personally I think it was a mistake to have these accessories installed (at least by Car Toys). I made the mistake of letting them install a stereo for me once and they screwed EVERYTHING up. They cut wires that shouldn't have been cut, they did poor splices (some were just twisted together & taped), they lost screws, etc. They also pried & bent some parts & broke some mounting tabs. Instead of enjoying my new stereo I became infuriated listening to all the new rattles coming from my dash. I ended up ripping it all back out, repairing their work, then putting it all back together. I went back the next day with a list of the missing screws/fasteners. It took an angry call to their manager (not there) before they would allow me access to the shop. One of the "installers" handed me a box full of bolts, screws, fasteners & misc parts (apparently from lots of cars) and said "If we have them this is where they would be". Sure enough, after a few minutes of picking through it I found everything on my list (although I'm not sure it was all from my Previa).

Sorry about the rant, but this is the type of work ethic you can expect from Car Toys & similar places. As a troubleshooter, I can't tell you how many times problems like this I've traced back to bad accessory installations. Of course the Previa is getting old so there's a good chance it's something unrelated. Since they were messing with the security system, I'm guessing the issue was created by them. In situations like this, as a troubleshooter, I would start out by going back into the areas they were working in and look for mistakes, bad connections, etc. If nothing obvious presents itself, next, as a troubleshooting measure, I would disconnect the accessory(s) and wire back to normal. It's usually pretty easy to figure out original wiring (just look for the "hack" stuff like scotch locks, cut wires, & electrical tape, remove it, then match up original wires using original color markings). If that doesn't solve the issue, at least it eliminates these things as possible faults & will make further troubleshooting easier. If the problem is found in a factory system, after the problem is resolved you can always go back and hook these items back up.

When it comes to factory security system issues, the most common problems are related to the door sensors. Here's a thread where this is discussed: http://www.toyotavantech.com/forum/s...at-on-the-dash. Good luck. Tim

[timsrv]

Aside from activating the horn flashers, headlights, & tail lights, the factory security system has the ability to lock doors, prevent doors from being locked, and can disable the starter. If more than that is happening then it's not the security system. Behind the dash, just above the driver's left knee, there is an ECU for controlling the system. I've never experimented with this before, but I suspect if you unplug this unit it might allow you to use the van with the security system deactivated. If I were troubleshooting an issue like yours I would at least try that to see what happens.

If you're driving down the road and the engine quits and everything goes dead (more than the things the security system controls), then I'd suspect a main power cable is bad or has a loose/corroded connection. The fusible link box attached to the positive battery cable is notorious for creating such problems, but your husband already checked that. I would also check the other end of that cable and both ends of the main ground cable (from battery to ground) to verify connection is solid on both ends. Good luck. Tim

[janeldavis]

Thanks again for your reply Tim. You are awesome. Your reply does make me think it might be the fuse box by the battery. The vehicle hasn't stopped running while I'm driving, those electrical components just go out. Then when I park it, the van won't start at all--no noise. When this first happened, we (after looking around a bit) took the fuse out and in again (the one by the battery) and everything was fine...until the next time we drove it and it did the same thing. However, wiggling that fuse box will make the locks lock. Soooo....I'm thinking we should investigate that fuse box more. Maybe it's spotty and only working sometimes. Also, the last time I tried by wiggling it, I did get it the van to turn over but not ignite/start. Maybe the fuse thing is also doing something weird to the security system?

Also, I'm wondering if the sliding passenger door has something to do with it. When we first got it, it unlocked with the driver's door master control. Now it doesn't and only works with the key in the passenger sliding door.

One more question--Do you know if there is an immobilizer in addition to the security system. I've looked around on the internet a little bit, but haven't found the answer. All I've found is the security system.

Thanks again. I'll post again if I figure things out. Hard to have time to fool around with this with 2 kids under 2 and a half

Janel