96 wiring differences & starter issues
Discussion
For reference I’ve got the yellow 4.5 we’ve had for years, registered in 98 actually built in July 97. I’ll just refer to that as the 97.
I got the two 4.2s last summer, the black 96 with everything removed & the crashed green one. I’ve moved everything over to from to the green one (details here if you hadn't seen https://www.pistonheads.com/gassing/topic.asp?h=0&f=6&t=2056150&i=0)
The black 96 has June 96 stamped into the chassis.
From what I've seen the 97 & 99 follow very closely with everything that is on the wiring diagrams on the Cerbera site, I think most of the diagrams on there are revision 3
I had to remove every control box & the fuse board from the 99 to put in the 96. I noticed when putting the fuse box in that a lot of the wires were different colours but the connectors were all the same. I did consider swapping the loom too but that seemed quite involved & the fuse board seemed like it must be the same part as all the connections fitted perfectly.
There is a totally different type of fuse board on the later cars, I’m not referring to that at all in this post.
I did want to check everything first but I haven’t found any wiring diagrams for the 96 yet, so I decided to just connect everything up & hope for the best. After a lot of general fixing broken stuff I got everything non engine related working fine so I decided keeping the 96 loom in the 96 car was the best plan & pressed on with putting the engine in.
The engine is in now, I wanted to get oil pressure up without spark plugs in. I had a couple of older batteries so tried them but got the classic click from the starter solenoid with no movement. The battery voltage dropped down to about 5v at the same time, I figured they were done so pulled the battery out of the 97. It cranked over fine with that in, it took a good few goes to get oil pressure. I stopped & left the battery to charge back up between goes.
I wanted to check I had a spark & good compression on every cylinder next. However part way into that it stopped turning over again & was back to only clicking the solenoid. The battery that had been turning it over fine a moment earlier was now dropping to 5v, the difference being it went back up to 12v as soon as I turned the ignition off. On the next go I think I heard a slight fizzy noise from the open boot & it stopped clicking the solenoid
I established that there the ignition control unit had stopped sending out any voltage down the white with red stripe wire.
This is where it gets confusing!
I then found it was only getting 12v in on one of the two inputs. This is where the 96 deviates from the wiring information out there. Everything available shows that the two input are spliced together. Checking them on the 97 it seems they are indeed connected (no resistance between them). However there was is no connection between them on the 96.
The red wire with the black probe from my meter stuck in is the one that wasn't getting any power:
(That is the 99 box in the 96 there)
I found it connects to this connector on the back of the fuse board:
(meter set to resistance there)
That is connector H, on the revision 3 diagrams it goes to thing like the lights and indicator ECUs, it has nothing to do with the starter. That connector for H on the 99 had different colour wires too:
Note the connector I had the probe in hasn't got a wire there at all in the 99.
I realised it connects through to fuse 13, unused in the 99 so it didn't have a fuse in. I put a fuse into to 13 but I still didn't get any power on either side of fuse 13. The 97 has got a fuse in 13 & it has a permanent 12v.
I found 13 connects through to O:
The one with my black probe in
I found there was an extra thick brown wire in the 96 that wasn't there in the 99, I wasn't sure what to do with it so just plugged it in next to the other (it's connected inside the fuse board like the reds are).
I guessed the extra brown must have been to go to O on the 96 as the other browns are spliced together to feed back into a number of the other plugs.
So I moved the brown to O:
That got 12v into 13 & then also back up to the ignition control box. It also restored the missing power to the passenger door motor which was nice!
With the connection to the starter off I could hear the front starter relay clicking again with the press of the starter button.
Starter relay is in the passenger footwell on the 96 & 97, it connects in where the main loom plugs into the engine loom. The 99 hasn't got any relays there for the starter.
(It would normally be tucked away!)
However with the starter connected I'm back to just a click & the battery voltage dropping again now. I'm thinking it must be a dodgy starter?
The thing that is really confusing me it how on earth it was working at all for a while in the middle there when the starter circuit wasn't getting any power!!
I got the two 4.2s last summer, the black 96 with everything removed & the crashed green one. I’ve moved everything over to from to the green one (details here if you hadn't seen https://www.pistonheads.com/gassing/topic.asp?h=0&f=6&t=2056150&i=0)
The black 96 has June 96 stamped into the chassis.
From what I've seen the 97 & 99 follow very closely with everything that is on the wiring diagrams on the Cerbera site, I think most of the diagrams on there are revision 3
I had to remove every control box & the fuse board from the 99 to put in the 96. I noticed when putting the fuse box in that a lot of the wires were different colours but the connectors were all the same. I did consider swapping the loom too but that seemed quite involved & the fuse board seemed like it must be the same part as all the connections fitted perfectly.
There is a totally different type of fuse board on the later cars, I’m not referring to that at all in this post.
I did want to check everything first but I haven’t found any wiring diagrams for the 96 yet, so I decided to just connect everything up & hope for the best. After a lot of general fixing broken stuff I got everything non engine related working fine so I decided keeping the 96 loom in the 96 car was the best plan & pressed on with putting the engine in.
The engine is in now, I wanted to get oil pressure up without spark plugs in. I had a couple of older batteries so tried them but got the classic click from the starter solenoid with no movement. The battery voltage dropped down to about 5v at the same time, I figured they were done so pulled the battery out of the 97. It cranked over fine with that in, it took a good few goes to get oil pressure. I stopped & left the battery to charge back up between goes.
I wanted to check I had a spark & good compression on every cylinder next. However part way into that it stopped turning over again & was back to only clicking the solenoid. The battery that had been turning it over fine a moment earlier was now dropping to 5v, the difference being it went back up to 12v as soon as I turned the ignition off. On the next go I think I heard a slight fizzy noise from the open boot & it stopped clicking the solenoid
I established that there the ignition control unit had stopped sending out any voltage down the white with red stripe wire.
This is where it gets confusing!
I then found it was only getting 12v in on one of the two inputs. This is where the 96 deviates from the wiring information out there. Everything available shows that the two input are spliced together. Checking them on the 97 it seems they are indeed connected (no resistance between them). However there was is no connection between them on the 96.
The red wire with the black probe from my meter stuck in is the one that wasn't getting any power:
(That is the 99 box in the 96 there)
I found it connects to this connector on the back of the fuse board:
(meter set to resistance there)
That is connector H, on the revision 3 diagrams it goes to thing like the lights and indicator ECUs, it has nothing to do with the starter. That connector for H on the 99 had different colour wires too:
Note the connector I had the probe in hasn't got a wire there at all in the 99.
I realised it connects through to fuse 13, unused in the 99 so it didn't have a fuse in. I put a fuse into to 13 but I still didn't get any power on either side of fuse 13. The 97 has got a fuse in 13 & it has a permanent 12v.
I found 13 connects through to O:
The one with my black probe in
I found there was an extra thick brown wire in the 96 that wasn't there in the 99, I wasn't sure what to do with it so just plugged it in next to the other (it's connected inside the fuse board like the reds are).
I guessed the extra brown must have been to go to O on the 96 as the other browns are spliced together to feed back into a number of the other plugs.
So I moved the brown to O:
That got 12v into 13 & then also back up to the ignition control box. It also restored the missing power to the passenger door motor which was nice!
With the connection to the starter off I could hear the front starter relay clicking again with the press of the starter button.
Starter relay is in the passenger footwell on the 96 & 97, it connects in where the main loom plugs into the engine loom. The 99 hasn't got any relays there for the starter.
(It would normally be tucked away!)
However with the starter connected I'm back to just a click & the battery voltage dropping again now. I'm thinking it must be a dodgy starter?
The thing that is really confusing me it how on earth it was working at all for a while in the middle there when the starter circuit wasn't getting any power!!
hoppo4.2 said:
these are from my early 96 if they are any help
Thanks, yes they are! I can see the thick brown wire connecting to O there. Also APM Andy confirmed that O should have a connection looped back from L, so I'm confident moving my brown wire there was correct now.
FarmyardPants said:
Is O the other side of the footwell relay (ie moving from H to O bypasses it)?
Not sure on that one, after all my messing about I decided I really should save everything down in one place on the new PC, so I went thought everything posted on this very useful link from ukkid35 that gets you to the archived copy of the Cerbera site while it's down: ukkid35 said:
There is a diagram for the internal connections of the fuse board on there I missed before, I did start to look at it but must confess as mine seems to be working ok now I didn't get very far with it...
I did try pulling fuse 13 out of the the July 97 built 4.5, doing that killed the starter & the passenger door motor, exactly the same as it had been doing on the 96, so the answer had been hidden inside that car all the time! I haven't pulled the fuse board out of that (it's never had much wrong with its electrics) so I'd rather not mess with it too much. I'm sure I'd find the brown wire going to O in that if I did look now.
So what I said about the the 99 & 97 both following the available revision 3 wiring diagrams clearly isn't quite right.
The hand book that came with the 4.5 shows this:
It shows fuse 13 as not used, that is clearly wrong!
I didn't get a hand book with the 96 but I think the correct 96 hand book is the one that is up loaded to the Cerbera site (you can still get to that from that web.archive link if you just navigate back on their site).
That earlier handbook says fuse 13 is for the the starter & drivers door lock, better for the 96 & 97 but still not correct. It actually sends the power to the input of the door control ECU that powers the motor that opens the door latch for the passenger door. So with fuse 13 removed on both the 96 & 97 if I press the passenger internal or external opening button the window will roll down but the door won't open. I waisted an enormous amount of time trying to work out what was wrong with the passenger door on the 96, because everything out there says the passenger door lock shares its power supply with the boot lock, my boot lock was working fine. So I was very glad to have stumbled across the answer to that while looking at the starter supply.
As I said pulling fuse 13 on the 97 instantly stopped the starter working too, so I still am still rather confused how it was working for a while when I had no power going to fuse 13 & no fuse in the socket in the 96!
Byker28i said:
This is from my 97 handbook for my 4.2
Thanks, yes that’s the same as the one on the Cerbera site. I assume there was just that one handbook to start with. Oddly the handbook that our July 97 4.5 came with, that has the incorrect missing fuse 13 layout I posted earlier, says copyright January 1997 in the front. So they were obviously intending to change the fuse layout (with the corresponding wiring changes) that early.
They must have made the new handbook to go with the new 4.5 so included all the changes they were intending. It has details for both the 4.2 & 4.5 in it, both with fuse 13 missing!
Interesting that you got the early handbook with your 97, I wonder if the kept giving out the earlier more relevant handbook with the 4.2 when they were giving out the other one for the 4.5s?
Also that early handbook you have describes the ventilation system correctly for our 4.5, where as the handbook it actually came with is wrong, it describes something more like the later cars system for the ventilation.
The handbook that came with the 99 says copyright October 1998, the fuse layout for the 4.2 & 4.5 (also ventilation description) is the same as the Jan97 one I posted with 13 missing but by 99 it was correct for the car. That handbook has the extra section for the Speed 6 in it too, on the fuse layout for that there is a note of caution in bold print saying to be careful as it has a different fuse board to the 4.2 & 4.5.
Byker28i said:
Yup handbook thats on the TVR site is mine, I digitised it some years back - took out the page with the details filled in.
Well thanks very much for doing that then, it's been very useful! If the TVR site comes back I would be happy to do the same with the later handbooks I have.
Byker28i said:
This is from my 97 handbook for my 4.2
For reference for everyone Fuse No. 7 15A is incorrectly labelledIt is actually "Boot lock, Drivers' door lock, radio"
Ask me how I know...
I had all of the parts ready to replace the driver's door actuator and after continuity metering all of the fuses and finding Fuse 7 to be blown and replacing it the driver's door lock came back to life. Before the window would drop, but the actuator would never fire and the door lock never unlocked
Gassing Station | Cerbera | Top of Page | What's New | My Stuff