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Wedge TR8 lights help needed

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PATR8

PATR8

Jedi Knight
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OK, I have trouble shot the lights thing to teh limit of my knowledge, I need some help. I took a working light motor out of my FHC 8 and put it in my DHC 8 and nothing, not even a noise. I pulled out my manual and was still unable to find a solution. Could some one explain the fuse portion to the lights to me? Any other Ideas where the problem could be? Thanks
 
Before you even start, you will need a wiring diagram, a 12 volt test light and a length of wire preferably with clips on the ends. If you have a spare battery laying around you can use that to put 12 volts where you need it to test things. You need to follow the electricity. Start at the switch. Once the headlight switch is turned on, it redirects the current to the lights and to the headlight relays(located beside the fusebox). Your most likely culprits are worn headlight switch contacts or a blown relay. Inside the switch, there are small white protrusions that slide against the copper contacts pushing them against each other. Over time these plastic protrusions wear down to a point where they no longer cause contact between the copper electrodes. Another common problem is green slime corrosion inside the switch. The switch should be wiped down and new red electrical grease applied. You can stick the test light into the back of the switch where the wire bullets get inserted to check for current. Check for current in and also check to see if the current gets switched out after the switch is thrown. Then check to see if the relay is getting this switched power. The relay has a constant power in and a switched power in. Once it receives the switched power, it clicks and sends power to the headlight motor. It is very complicated. A wiring diagram is essential.
 
I Have swapped out the light swithch from my FHC which I know works and nothing, I know the motors work. so teh problem lays between teh two. I do not know which relays go to the lights, as I sit here at work I recall two black cicular relays and one Blue circular relay. Any ideas what relays go where? No ideas what goes where. Trying to track the wires from the switch is useless since it goes into a bundle. It looks like each light motor has it's own fuse labeled light dip. So that is where I am....
 
one time i had one of the connectors on the fuse panel come off and I lost power to the lights; motors still worked but no lamps. I am not home right now, but the power should go through one of the fuses, to the contacts of the relay (coil has different source) then to the motors. I (mind you this is from memory) don't believe that power is directly from the switch to the motors. check the connections at the fuse panel -- you may have to pull it out of the glove box to be sure; I did.
 
Under the steering cloumn there is supposed to be a green wire that attaches to a clip. I have seen these come off and guess what, no lights. Check that first! Before you tear your car apart. If you do not know what I am talking about let me know and I will take a picture of it for you. As I am sure everyone has told you as well, make sure all your grounds on the car are tight and clean!


GL!


Rod
 
I tell you what, I am perplexed, I have checked the grounds, the switch, the motors, it has to be between the switch and the motors. I know the green wire that clips to the ignition, it only makes a buzzer go off in my fuse box area. I thought that it was a seat belt warning. Will test that theory tomorrow. The turn signals seem to has some lucas in them too, worked on Sunday, did not work yesterday, and worked half of today.
 
Are you talking about the headlights or the headlight motors? They are controlled by the same switch, but that is it. After the switch the wiring for the lights and the wiring for the headlights are different. The only common point is the grounding location inside the engine compartment. Since you said you replaced a motor, I assumed you were having a problem with the motors not cycling. If you do not have a wiring diagram, you will have a much harder time tracking this down. You will be dealing with several different colored wires for each motor. There is no easy fix here. You need to follow the current to find the problem. Somewhere along the maze of switch, relays, fuses, and connectors, there will most likely be an open circuit. It could be a cut wire, a burnt fuse, or just a bad connection that needs cleaning. You need the wiring diagram, a basic knowledge of circuitry, a test light, and some patience. There is a nice wiring diagram in the back of the factory shop manual. The diagram for a later TR7 would also work as the headlight wiring is the same. You might be able to find an on-line copy of one to print out.
 
IT is the light motors not cycling up or down. I have a tr8 repair manual that has a wiring diagram in but I just have not had the time to get deep into it while I help my son's friend fix his car the past few days. I have found and fixed two broken wire connections but this looks like a in depth problem to figure out. I have started the tedious test light process trying to find where the powere stop. I am having trouble figuring out the breakers in the fuse box.. That is the part I do not understand and have yet to figure out from my repair manual
 
In a nut shell, here is how a relay works. There are multiple terminals inside. One terminal is supplied with power all of the time. This power is just waiting to be sent out. When you turn on the master light switch, a second "switched power" is sent to the relay. The switched power, along with a black ground wire, combine to activate a switch inside the relay. That is the click you here behind the dash board. Once that intenal switch clicks, the constant power is sent to the headlight motor. The manner in which the headlight motor cycles and shuts itself off is another topic.
 
I was curious, in teh fuse box area, there are 2 black relays and one Blue one, I assume the black relays are for the light motors, but what about the blue one?
 
one should be a starter relay
 
OK, I assume the Blue one is the starter and the two black go to the relays, I will give Woody a call here soon to get some hints. I have all evening to work on it
 
don't you have a newer wiring harness? there should be more than three relays I think. Like one for the AC system and maybe some kind of circuit breaker for the headlamps. After next week, if you are still having a problem, I can help you more.
 
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