Dear all, I have a weird headlight problem. On the respective the light switch positions following happens: - normal headlights: left light working, right side does not work - high beam: left highbeam on, left normal off, right highbeam on, right normal also on (!) Bulbs are ok, fuses are ok, relays are ok (switched them to test). What can it be? I run out of ideas. Best regards Harry
check the diodes for the motors/headlights or search for " headlight + diode " and the threads should come up . i cant remember the specifics, but there are threads on this that may help you.
Harry, get the buckets to come up. then disconnect the battery. remove the covers from around the headlight and chck the wires and the small diodes. the grounds (earths) come right off the motor for the lights and go to the chasis. its best to go ahead and remove / clean them while you are in there.
Sounds to me like two burned out filaments. (Always start with the simple!) The highbeam lamps only have one filament but the low beam lamps have both a low beam filament and a high beam filament, and when you switch to high beam position the low beam lamp should switch from the low beam filament to the high beam filament. Sounds to me like the right side low beam filament is broken and the left side low beam lamp's high beam filament is broken. That's where I would start.
Thats great advice mate. And its where you would normally start 1st. But........in his 1st post he mentions that the bulbs are ok? Maybe they aren't? I dont know!
I do not have the car right here, but I assumed the low beam and high beam bulbs have both only one filament. I have replaced the right low beam bulb with a 55W H1 (it was H1 before). But for sure, I will have another look. Question: I assumed that the low beam lights are off when I switch to high beam. Is this correct?? Best regards Harry
On my car series 1 GT4 1st position is parking lights.2nd position is low beam.3rd position is high beams only but in this position if I pull the stalk towards me the low beams also come on.I initially thought that you had problems with the headlight motors.Also another funny thing on my car is that one of the fuses powers up the front left park light and rear right park light and another fuses powers the front right park light and the rear left park light.I know its crazy but it doesn't bother me
Not on the GT4's I've inspected, but these have all been USA cars, and there might be a difference between different countries lighting regulations that would affect this. On the cars I've looked at the low beam comes on in the first position and in the second position the high beams come on and the low beam lamps switch to the high beam filament. BUT during this time the USA had laws mandating crappy lighting for all cars, so a euro setup might be differnt.
Now the lights are working again. With a friend, I did test it all the way upstream from the lights themselves. Bulbes in the early cars ('74) have H1 for both, dipped and main beams. Wiring diagram suggests that there is a double filament bulb outside, but it is not and the respective wiring is not there. Next thing was to check the resistance of the wiring incl. bulbs from the fuse box (without fuse) to mass. Result: wiring is ok. Then seeing what happens when the lights are switched in terms of voltage at the fuse box. There we found an intermittent work/failure mode. Diagnosis: the column switch has to be taken apart to be cleaned/soldered/repaired. This will be next, first I need the ring nut tool for the steering wheel. Regards Harry
It's your fuse blocks!!!! I had the same thing. There are two fuses involved (I believe #3 and #4 on the lefthand block, but it has been a while - it says so on the covers), each powering one of the main lights, and A BRIDGE, BEHIND the fuse block. The rivets that hold everything together double as contacts between the tabs and the bridge. These will have lost contact (or have intermittent contact). What you want to see: ================== normal light: the outer lights burn High beam: all four lights burn. How it works: =========== Normal operation will have you power one fuse (of the lefthand normal light), and the bridge bringing the power to the righthand fuse to get the righthand light on. High beam will send power to the righthand fuse only, and the bridge is used to get power to the lefthand fuse. Now what happens if this bridge loses contact? Normal operation will see only lefthand light (no righthand) High beam will see high beam lights (through their own fuses) and the righthand light (no lefthand), as opposed to the intended all four on. Sounds familiar?? The solution? ========== 1) Get a pair of Birdman's fuse blocks and forget about the whole issue or 2) Take the fuse block out (no need to disconnect all the wires, just make it accessible to a soldering iron), drop a few drips of solder on the joints of both fuses and the bride (front side AND back side - don't ask how I know) and admire the results. For now, I've done option #2. Problem solved. Hans 308GT4 series 1, 1974
Hans, great, this makes everything clear! I was really lost on this. I will try the solder solution as well and post the results Regards Harry
If it helps (a bit late I know) , there is a large format pdf of the wiring diagram on my website. I had it printed on D size paper, makes it almost usable It has helped me decipher the wiring on a few occasions, esp for finding the grounding points. Gerrit http://dino308gt4.com
Hi Gerrit, good idea to print it on larger paper. It is a pain to follow the lines in the small prints! Regards Harry
Today I have taken out the fuseboxes and soldered all rivets, bridges and joints together. All in all this is a 2-3 h job. This will work, new fuseboxes would be the better, cleaner solution. Everything is working now. Thanks everyone for the help, this was not an easy one to find. Regards Harry
You're welcome, glad to hear everything worked out. You could buy a pair of new fuseblocks from birdman (glass fuses)(www.birdmanferrari.com). Or alternatively, there is a thread in the Testarossa forum from a guy who is doing blocks for blade fuses that can take the stock fuse covers. Both are not expensive. Hans
Dear Hans, I support your recommendation to all who have similar problems to buy new fuseboxes from the start. Alternative: - I have taken out the fuseboxes - soldered together every single contact in both fuseboxes - put them in again, which is a PITA due to limited space in the corner of the glove-box (series 1 car) Lessons learned: repairing the old fusebox is too much work without the appropriate amount of fun. Regards Harry
Harry, I've also got a series 1. Never bothered to take the boxes out. Just unbolted them to be able to reach the backside and soldered them with all the wires still in place. The GTB/GTS seem to be much easier to work with than the GT4 in this respect.... Hans (hoping to take delivery of my new fuse boxes within the next few weeks)
My hands were too big to do that in the glovebox. And I found some more connections loose, so I was glad that I took them out.
