Okay so. First off I'm new at electrical work. Bare with the possibly stupid questions because I could really use some input with the heating system/blower in my 1990 v6 pickup. My baby n my beast.

About a year ago it started only blowing on full power. Swapped out the regulator and it worked fine on all speeds thrill the other day. Had the heat on, turned the truck off for 15min or so then when I cranked her back up. The blower was dead. Straight nothing.

A few days later I tore the passenger side dash apart to get at the 30amp fuse. It was fine but I swapped in a new one anyways. Took a look at the regulator which looked like it did the day I installed it. I read a few posts and started combing the internet. When I flick the power back n forth I can hear and feel the relay switch clicking, which from my research means it's functional. I decided to pull it and visually inspect it anyways. It was alll wet as soon as it freed up, on the inside it's all green and corroded. Means she's burnt right? Are 30 amp relays universal? It's worth picking one up regardless is what I'm thinking.

Secondly. During all this electrical and melee of wires I decided to pick up a 12v test light at Canadian tire (my home away from home haha). I havnt tried it out yet but I'm planning on getting a few good hours of work done on the truck next weekend. So my question is, how do I properly check the blower system with the test light? That way I can narrow the problemed section down.

Anybody with any input is totally welcome. I'm all ears. I know several of these other threads have helped me out so I thought I'd take a stab at my own.

Thanks everyone. Happy trails.

 

Wet, green, and corroded? Electricity doesn't like any of those three. I doubt the relay is "burnt," but if it isn't otherwise dead yet it will be soon. So, yeah, replace it. It's not universal, but Autozone carries them for $20. You won't have trouble finding the right one. When you replace it, examine the socket carefully. The relay isn't the only thing that can corrode. (and you're going to need to find the source of that water, or you'll be back to square one in a hurry.)

A "test light" is 20th Century technology (and it will work for troubleshooting your truck, because it's 20th Century technology too!) But I'd advise you just jump right up to the 21st Century and get a multimeter. http://www.harborfreight.com/7-funct...ter-90899.html You'll find it much more capable and easier to use.

Here's the schematic: http://web.archive.org/web/201102052...g/25heater.pdf Just follow the voltage through the relay until you find where it's missing.

 

are you taking about the relay here?

did it look like this?



on my project 4runner thats what mine looked like. I believe it was from having a leaky windshield. I also had issues with the circuit opening relay which is a little ways below that.

I got a replacement on ebay cheap. note if you have a 4runner with rear heat there are two fan relays

 

Yeah it totally looks just like that! And I'm pretty sure I have a leak around the windshield as well. Did your blower work with the old relay? And what does the circuit opening relay do? Cause I've been having some shorting out issues that I can't pinpoint.

 

The Circuit Opening Relay (COR) powers the fuel pump. Turning the key to start closes the COR, then once the engine starts sucking air the VAF powers a second coil in the COR to hold it closed once you let go of the key. (This way, if you get into an accident that breaks a fuel line, the fuel pump will shut off as soon as the engine stops -- without you doing anything.)

Obviously, none of those components like water. But if you had a problem with the COR it would most likely end up as a no-start.

 

That all makes sense and sounds oh so familiar. I've had a few no starts recently. Same kind of deal, kill the engine for a short period then nothing when I get back. Just a loud click when the key was turned and nothing after. No battery power goes to anything until I pop the hood, disconnect then reconnect the battery (takes a few trys sometimes) do you think this could be due too a wet COR?

Maaan I love yotatech. This place and you guys keep my rig and I alive hahaha.

 

no, the blower didn't work with the relay like that. go ahead and replace it.

the circuit opening relay issues caused the fuel pump to not get power for me. when I bought my 4runner the previous owner had run a switch and separate power for the fuel pump. The engine will still crank with the circuit opening relay non functional, just the fuel pump wont run so it sounds like you have another issue also.

 

Probably not; the COR only powers the fuel pump. It will not (directly) interfere with the starter. ("Loud click and nothing" sounds like not enough battery voltage to turn the starter - you're hearing the solenoid. But why? If you have a short somewhere, it could load the battery enough to keep it from having enough left to spin the starter. Shorts can be anywhere, but a short that would limit the starter has to be pulling enough amperage that you should be able to smell smoke!)

MMA_Alex - Do you still bypass the COR with a switch? You might consider reinstalling the COR for the reason I give above.

 

no its all fixed now. i was saying when i bought the truck it was jury rigged. I wasnt getting power to the fuel pump wires. replacing the badly corroded circuit opening relay fixed that

 

 

sorry for any confusion above. the only reason I mentioned the circuit opening relay is because i had the same issue with blower relay corrosion, which i believe was due to the leaking windshield, and it also dripped onto the COR which is in the same general area