cold weather electric starting problem '96 B4V

B4Moody

Member
Joined
Dec 28, 2021
Location
California
TDI
96 passat
Good morning- Merry Christmas. My latest tdi has a cold electric issue. if the weather is mildish, it seems to be less problematic. turn key to heat glow plugs, maybe 2x or 3x before turning over, (30 degrees or so outside) start car. smoke from under dash, turn car off. i discover previous owner had a 40 or 50 amp fuse wired into what i have to assume is glow plug circuit. I cut it out, wire in a circuit breaker fuse, 20amp. Upon a new cold morning, i repeat, start car. after starting, i hear the breaker pop, but vehicle continues running. So I am not TOO worried. I hear it reset. I hit rear window defrost, and I hear it pop again. when it resets, i don't hear anything, it continues running. I wipe snow off windows and roof while it warms up and I head down the road. it seems ok, but i would like to get to the bottom of what is causing this problem. i have basic electric skills but no vagcom, just a standard obd scan tool. any direction would be appreciated. mike
 

ToddA1

Top Post Dawg
Joined
Aug 3, 2011
Location
NJ 08002
TDI
'96 B4V, '97 B4 (sold), '97 Jetta (scrapped)
Not sure why you replaced a 50A with a 20A…

Read this:

-Todd
 

B4Moody

Member
Joined
Dec 28, 2021
Location
California
TDI
96 passat
Todd- i replaced the large fuse wired inline, because it got so hot it almost caught fire. whoever owned it before, put this large fuse in there, when i could see from a wiring diagram, the interior fuse is 20amps, and the engine side fuse is 50a. if it irritates you to read posts and answer questions, why do you bother? I didn't even ask which fuse or relay is for the glow plugs. the fact remains, when it is COLD outside, the vehicle is cycling high amperage under the dash, that the previous owner tried to fix with a fuse that is too big. i reduced its amperage to 20 so nothing would catch on fire which seemed practical to me. BUT, the fact remains, there is something wrong, otherwise the last guy wouldn't have put in that huge fuse.
 

ToddA1

Top Post Dawg
Joined
Aug 3, 2011
Location
NJ 08002
TDI
'96 B4V, '97 B4 (sold), '97 Jetta (scrapped)
if it irritates you to read posts and answer questions, why do you bother?
I did read your post, which mentioned you replaced the existing fuse with a 20A breaker.
Did you read the 2nd post, which mentioned 20A is too small?

I won’t bother replying to any more of your threads. Take care.

-Todd
 

Steve Addy

Top Post Dawg
Joined
Aug 7, 2002
Location
Iowa
TDI
97 Mk3
I think we need to discern where this new 'wired' fuse / breaker thing is before we start to figure out what might be wrong.

There are two sets of GP's on this engine, engine GP's (qty 4) and coolant GP's (qty 3), and I'm not sure which one you're talking about since they're both under the hood. Control for the engine GP's is under the dashboard and control for the coolant GP's is under the hood.

The engine GP's are around 11 amps each in draw, or at least that's the advertised amperage. I've seen both 50 and 80 amp maxi fuses under the dashboard, the 50 amp is what I would consider a minimum for engine GP's without blowing.

The strip fuse under the hood is for the coolant flange GP's and that's also to be a 50 amp, but it's a strip fuse. Those older style GP's (from the 1.6 diesel era) are around 14 amp draw IIRC and so a 50 amp strip fuse is sufficient.

In order to resolve the problem we need to know / see what we're dealing with and where it is in the engine compartment.

Steve
 

B4Moody

Member
Joined
Dec 28, 2021
Location
California
TDI
96 passat
Thanks Steve. I had an early look this morning. the fused wire appears to be coming from the battery, into the fuse block. Once thru the firewall, it Y's to the main fuse panel, which is the part fused. the other leg of the 'Y' goes back out through the firewall, and is in a bundle of wires. It is difficult to see where it goes. you will see in my picture, a large gauge wire connected to the corner of the fuse panel, and the fuse in position 12 is a "167" relay. my b4v is supposedly a wolfsburg passat made in germany but i have no idea if this fuse panel is original or not. there is a small computer just above the panel labeled "RdW"

 

Steve Addy

Top Post Dawg
Joined
Aug 7, 2002
Location
Iowa
TDI
97 Mk3
Someone has been messing with the relay panel and that's the most identifiable problem. A 167 relay is a fuel pump relay for gasoline powered cars, and someone has put it in the socket where there (maybe) should be a 103.

The 'computer' you mentioned is actually the convenience module which can also be a problem but generally if they work right they're ok. It does handle some security functions (sounds alarm etc).

In this case I think Todd is right, you should review this thread for information about your fuse box and what GP relay goes where. Depending on when your 96 was built it could be needing a 103 in position 12 (where 167 is) or it might need a jumper in that position, and actually having a relay there is bad if it's not required.

Check the relay fuse box info thread that Todd pointed to and see if that helps you on your way here.

Also, you mentioned smoke under the dash? That's probably related to some things not in the proper place or insufficient in amperage. As I mentioned before then 50amp maxi fuse is a must have for the engine GP's to work since they draw around 11 amps each.

I don't think the fuse box is a problem but that relay in position 12 has got to go...it's not the right one at the very least and depending on what GP setup you do have you may not need a relay in the position at all. Cars with the large 180 relay in line with the maxi-fuse do not require any relay in position 12 of the relay panel, as you will find in that thread I've linked to.

Steve
 
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Steve Addy

Top Post Dawg
Joined
Aug 7, 2002
Location
Iowa
TDI
97 Mk3
…removed by moderator…
Your complaint is out of line, if you had read the whole post you'd realize that Todd did nothing but point the guy to the SAME THREAD that I pointed him to. And that's after the OP started arguing about the amp rating necessary for glow plugs, 20amp, which is ridiculous. And the response about the 20a fuse replacement situation was echoed by others also....

Todd did nothing wrong here.

Steve
 
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kemalik84

Veteran Member
Joined
Nov 5, 2017
Location
Austin Texas
TDI
Jetta Sportwagon TDI, Jetta Sporwagon, B4 97, B4 97,B4 96,B4V, MK5 TDI Jetta
Your complaint is out of line, if you had read the whole post you'd realize that Todd did nothing but point the guy to the SAME THREAD that I pointed him to. And that's after the OP started arguing about the amp rating necessary for glow plugs, 20amp, which is ridiculous. And the response about the 20a fuse replacement situation was echoed by others also....

Todd did nothing wrong here.

Steve
I know it was sarcasm about the guys mistake..putting a 20amp in 50amp..im.just joshing with some typos.
 

ToddA1

Top Post Dawg
Joined
Aug 3, 2011
Location
NJ 08002
TDI
'96 B4V, '97 B4 (sold), '97 Jetta (scrapped)
I know it was sarcasm about the guys mistake..putting a 20amp in 50amp..im.just joshing with some typos.
I don’t think it was sarcasm. What was the ABC reference about? You mad at me, lol…..?

-Todd
 
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kemalik84

Veteran Member
Joined
Nov 5, 2017
Location
Austin Texas
TDI
Jetta Sportwagon TDI, Jetta Sporwagon, B4 97, B4 97,B4 96,B4V, MK5 TDI Jetta
I don’t think it was sarcasm. What was the ABC reference about? You mad at me, lol…..?

-Todd
No sorry that was typo it was transposed from a Google search for ABC near me...I was looking for a good place to get general tzao..not redevelop related just transposed from my pc
 
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B4Moody

Member
Joined
Dec 28, 2021
Location
California
TDI
96 passat
i have truly never meant any disrespect. I did go look at the relay thread, studied it, looked at my car, and the "hack" under the dash still doesn't make sense. I do know now that the first step was putting in a correct glow plug relay. I finally got one and did that. car starts no problem. But it seems the starter gear doesn't retract real strong and the key switch spring doesn't return to run very positively. I think this is what overheats the fuse. this fusable link like splice that was 40 amps is not factory at all so it mystifies me.
 
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