Fuse #46 keeps blowing (fuel and temp gauge)

[adamb]

I have a 1998 318ti with an M44 engine. I have searched but could not find anything specific to my case. My fuel gauge and temp gauge fuse keeps blowing. Fuse #46. I haven't found the source and all other fuses seem to be fine. The problem started about a month ago in the heat, i was walking to my car from getting out of class and unlocked my car. I noticed that only one side of my parking lights were working when i hit the unlock button on my remote. (I have aftermarket angel eyes with HIDs installed.) Normal operation of the lights was working just fine, no shorts of any kind. Just when i lock and unlock my car the passenger side of my parking lights wont light up. It seems that when the temperature gets above 70 degrees outside the fuse will blow. I did the bad thing and replaced it with a higher fuse but it also kept blowing. No other problems with car and drive ability remains fine. No overheating.

I found this post but it does not go into detail to much about the problem and the fix. http://www.318ti.org/forum/showthread.php?t=24558

Need some help here guys. I was thinking maybe i need to replace my thermostat?? If any one has information on the parking light problem, that would be much appreciated as well. Thanks for all your help guys!!

[3.2TI]

Use a higher amp fuse and see it blows. Maybe your lights are juicing up the amps. Make sure they are well grounded and not pinched wires on your lights. I am sure your lights are the problem.

[adamb]

I believe the original fuse is a 15 and i have went all the way up to a 30. At times the 30 amp will blow. I just keep swapping fuses. Ill have to find some time to take the lights off the car and just check all the wires... Any more ideas, suggestions or questions let me know.

Thanks a lot.

[Shellback]

http://www.318ti.org/forum/showthread.php?t=36096

If its the same issue, the culprit was the tail lights.

[Michael_M]

Just an Advice, Never ever replace a fuse with higher rated one, it might burn your wiring loom and that costs a fortune to fix as it'll be all custom made!

[adamb]

I am aware of the result of going to a higher fuse. So far no other problems have been cause to to the higher fuse. When I have some free time om going to have to dig a little deeper and check out the tail lights and head lights. I don't think i will find any problems due to the fact that i haven't altered the status of the front or rear lights in any way for a couple months now.

Some suspicious are telling me maybe a possible bad thermostat?

I don't have any other blown fuses except for fuse 46. Are they are other fuse boxes on the car other than the one in the engine bay?

[John Firestone]

Originally Posted by adamb

I am aware of the result of going to a higher fuse. So far no other problems have been cause to to the higher fuse....

Are you really sure? If there are no other problems, then why does the fuse keep blowing? Often, when someone tries a bigger fuse, they end up melting the wiring in some tediously inconvenient spot, such as under the carpet. Then instead of perhaps one problem, they have at least two.

I suppose if you end up torching the car, that will solve everything – but seriously, please don't substitute a bigger fuse.

[John Firestone]

I had a quick look at the BMW ETM (wiring diagrams). F46 has some thin, 0.35 mm^2 wire on it, which, for all I know, might become incandescent on a 30A fuse.

[Michael_M]

is it standard or automatic ?

[adamb]

It is an automatic.

Some updates on the problem.. It is getting cooler outside so my fuse has not blown. Had the correct 15 amp fuse for a couple weeks now. I'm going to see if I can locate the aftermarket alarm module and check that out.

Does anyone know where the engine grounds to the car frame at all? Is it different from each car or was it in the same spot for every car built?

Still lost as to what the problem might be.

[adamb]

Took out the glove box and found the alarm module. No problems or wires disconnected. Trying to hook up a better ground to the horn for the alarm.

I hooked up a continuity tester to test all my fuses, none of them were blown however the tester didn't light up on a few of them. I don't know the reason for this.

Fuses that didn't light up:

02 - Fuel evaporation control (4 Cyl)
11 - Low beam headlight, left
12 - low beam headlight, right
15 - front fog lights
16 - Air Conditioner, Aux Fan
18 - Fuel Pump
21 - ABS, ASC
22 - Front fog lights
23 - Air Conditioner, Heated rear window, heated rear window blower, heater control,

turn indicator lights, headlight flasher, OBC check control,
24 - Parking Aid, Heated Spray nozzels
25 - High and Low beams (left and right)
26 - Motronic
27 - Instrument Cluster
28 - Automatic Transmission
29 - high beam, left
30 - high beam right
42 - Airbag, Belt tensioner, belt catch, rollover protective system
43 - Central locking system, inside mirror, reading light, make-up mirror, Radio remote

control, Telephone
44 - Glove box light, Radio, Wipe-wash system
45 - Immobilizer, OBC check control, outside temp display
46 - Clock, Instrument cluster, Brake lights, OBC compact,

I don't have some of the options like OBC and such.


Any insight into my continuing problem would be much help.

Thanks guys!

[Michael_M]

Originally Posted by adamb

Does anyone know where the engine grounds to the car frame at all? Is it different from each car or was it in the same spot for every car built?

Well, It is fixed in all cars, but there is a lot of grounding contacts varies from the hood, beneath the dashboard and the trunk.. For that I might suggest to download the 318ti ETM (Electrical Schematics manual) and start from there..

Regarding those fuses that didn't lit up that doesn't make sense really.. you tested the fuses or the fuses female terminals ?
Normally if they're powered or even not they should give you zero resistance when doing a continuity test, if your car is not equipped with some items like OBC or anything then normally you won't find fuses there so I believe you were testing the female terminals of the fuses ?!!

Pictures will help now!

[adamb]

The issue with the fuses and the continuity tester was solved. I turned the car on and then i got a good test from the continuity tester.

Still have the problem with the alarm and the parking lights/halos on the passenger side. But now i have to buy a new H1 hid foglight =(

[John Firestone]

Hmmm. I would need to use two different testers, one "in circuit" and the other "out of circuit" to do what I think you want to do.

I would need to use a continuity tester on a fuse I had removed from the car: to check if it had been blow.

I would need to use, a voltmeter on the empty fuse socket: to check if the fuse will see voltage when I later plug it back in.

Are you trying to test both at the same time?