I have trouble with my tail lights. They don't switch on unless use a jumper wire in the tail light Relay socket to close the circuit manually. Relay and fuse check out okay, so I pulled the Integration Relay #2, AKA headlight retraction relay in the blue case behind the fog light switch. I thought I would see a burned circuit board or transister, or other obvious source of a problem, but instead it all looks fine. The circuit is a bit complicate. Does anyone have a circuit diagram or experence with this relay board? Its a mess to trace the circuit by inspection. Thanks.
Light retraction relay circuit diagram
- Thread starter bgim
- Start date
Which pins are you shorting on the tail light relay to make them work? And what happens when you connect pins 2 and 18 together on the IR 2 connector with the IR relay out? What happens when you short pin 13 to ground with it in?
jetjock;1008980 said:
I just checked it.
connect 2 and 18: tail lights come on.
Short pin 13 to ground wiht IR2 relay in: nothing happens.
I have the relay, have identified relevant wires, resistor, ?diode, transistor and IC, visually everything looks fine. It would be fun to learn how to fix the relay, but I don't have specs for the IC or the transistor, and I'm a beginner with electronic circuits. Any other info or ideas for fixing it, or is it a lost cause?
THanks again.
Personally, I went to a junkyard, and yanked a couple.
Paid $10 for 2 of em and they both work fine (have a backup now). I took the relay apart as well and could smell anything burnt or see anything burnt.
It's a fairly complet little board, and it wasn't worth it to me to try and repair it as the TSRM's procedure is simply to replace it...
Paid $10 for 2 of em and they both work fine (have a backup now). I took the relay apart as well and could smell anything burnt or see anything burnt.
It's a fairly complet little board, and it wasn't worth it to me to try and repair it as the TSRM's procedure is simply to replace it...
What Poodles said. I just wanted to make sure it was confirmed as the problem. Fwiw I think you did great getting as far as you did the way you did.
If you would like to try a repair the odds are it's the transistor. If you know which one it is (follow pin 18 to find out) try replacing with any small signal NPN. Use your meter to test it first.
If you would like to try a repair the odds are it's the transistor. If you know which one it is (follow pin 18 to find out) try replacing with any small signal NPN. Use your meter to test it first.
Thanks both of you, I'm sure you are both right. If I had sense I wouldn't be messing with a 21 year old car to start with, but it keeps me off the streets. If I find something interesting trying to fix the board I'll let everyone know. Its faster to swap the transister than find a junk yard in Michigan with 20 year old Japanese cars, so repairing the board is good if it works. I have a spare car so I can get the expected voltages from testing the part on that car, and if I get organized I'll post that too.
Strange thing is, I'm fixing the car I got as a parts car. Once I found it was getting 0-60 mph in less than 4 seconds without the boost controller or a skilled driver, I started wondering what the heck I had under the hood, and I can't bring myself to use it for parts. Looks like hell, though.
Strange thing is, I'm fixing the car I got as a parts car. Once I found it was getting 0-60 mph in less than 4 seconds without the boost controller or a skilled driver, I started wondering what the heck I had under the hood, and I can't bring myself to use it for parts. Looks like hell, though.
I THINK the same relay is used on other cars of the era... but someone would have to confirm the part number in the EPC for other cars...
I have some follow up, in case anyone stumbles on this thread later. I swapped the IR #2 from a 1989 NA supra. It looked the same, worked great. Somehow it also seemed to resolve intermittently dead reading lights, or perhaps it was just wiggling wires that did that.
Now for the cause: THis car had aftermarket fiberglass bumpers that were bolted on, but the wheel well covering material was missing. The left quarterpanel was rusted through under the aftermarket bumper, leaving a 5 inch hole. Over a michigan winter water and mud and salt sprayed into that hole and left a pool of standing water in the trunk underneath the trunk floor where it was not visible. The green wire from the tail light relay was under water, as were all the wires in the same bundle, but the tail light relay had a splice as it splits to the various lights it powers, and that splice was right in the puddle. THe wire had rusted through. The tail light failure sensor looked water damaged, but turned out to be fine. The TSRM recommends testing the wiring to the taillight failure sensor to detect a bad board, rather than testing the part directly. This worked in this case: the wire from the tail light relay had no power and was floating (not grounded), but on the relay side, it was shorted (rusted) to ground. The tail light relay and fuse tested fine, but the IR #2 ( headlight retract relay ) appears to have been partially damaged, perhaps by the short circuit.
Since the IR#2 controls other systems also, and it coordinates this all through a single integrated circuit chip, I wonder if it could contribute to bizarre symptoms if part of that IC is malfunctioning.
I also wonder if any of the other postings about the taillight failure sensors going out are actually problems wiht IR2 or with damaged wiring?
BTW, if anyone should need to buy this part, I offered $20 for one of those IR#2 parts, untested, on Craigslist and got flamed for lowballing. Then I found it at the toyota slavage yard online for $25. List is $180. Dealer cost about $130 new.
Now for the cause: THis car had aftermarket fiberglass bumpers that were bolted on, but the wheel well covering material was missing. The left quarterpanel was rusted through under the aftermarket bumper, leaving a 5 inch hole. Over a michigan winter water and mud and salt sprayed into that hole and left a pool of standing water in the trunk underneath the trunk floor where it was not visible. The green wire from the tail light relay was under water, as were all the wires in the same bundle, but the tail light relay had a splice as it splits to the various lights it powers, and that splice was right in the puddle. THe wire had rusted through. The tail light failure sensor looked water damaged, but turned out to be fine. The TSRM recommends testing the wiring to the taillight failure sensor to detect a bad board, rather than testing the part directly. This worked in this case: the wire from the tail light relay had no power and was floating (not grounded), but on the relay side, it was shorted (rusted) to ground. The tail light relay and fuse tested fine, but the IR #2 ( headlight retract relay ) appears to have been partially damaged, perhaps by the short circuit.
Since the IR#2 controls other systems also, and it coordinates this all through a single integrated circuit chip, I wonder if it could contribute to bizarre symptoms if part of that IC is malfunctioning.
I also wonder if any of the other postings about the taillight failure sensors going out are actually problems wiht IR2 or with damaged wiring?
BTW, if anyone should need to buy this part, I offered $20 for one of those IR#2 parts, untested, on Craigslist and got flamed for lowballing. Then I found it at the toyota slavage yard online for $25. List is $180. Dealer cost about $130 new.
