Electrical Connector Conundrum
Discussion
Hello guys. I'm looking for some collective brainstorming on how best to solve a problem of auto electical connectors losing electrical continuity.
I have a 23-year old Nissan Primera which has been causing me headaches with the Airbag Light turning on and off randomly. However, I've narrowed the problem down to the multi-pin electrical connector onto the instrument cluster, or as Nissan call it, the Combination Meter. This became apparent when the Fuel Contents Gauge and RH Turn warning light also started playing up. An Airbag Light on and a non-functioning Turn warning are both MOT failure items, so I need to fix it. See the following photos: -
Hopefully you can see my added labels as the where the offending pins are. I've disconnected, cleaned (although they didn't appear dirty) and reconnected each plug and also removed some of the tape from the wiring looms to try and ease any strain on the connectors. The RH Turn warning seems OK now but not the other two problems. If I reach my fingers over and press on the top of the grey connector where pins 12 and 20 are, all is well. But I can only do this with the trim removed and the cluster unbolted. By the time everything is reassembled, the problem comes back.
I don't fancy replacing the connector (if I can get one) as the loom doesn't come out very far from the dash. How can I make the existing connector seat down better for good continuity? The single locking clip is presently working, but that's only in the middle and perhaps age and heat has distorted the plastics?
What about: -
A. Using a rapid curing epoxy resin or superglue, sparingly on the connector shell. I'd need to hold it firmly down until set.
B. Using some kind of conductive grease on the pins. (Risk of causing short-circuits if it goes everywhere.)
C. Inserting a sliver of solder into each pin socket. (Don't want to bend the tiny pins and make things worse.)
D. Drill some holes (<1mm) and use 24 swg locking wire to firmly hold the connector halves together at each end. Obviously I'd need to route the wire clear of the contacts.
I must say I'm leaning towards 'D' but any other suggestions would be welcome.
I have a 23-year old Nissan Primera which has been causing me headaches with the Airbag Light turning on and off randomly. However, I've narrowed the problem down to the multi-pin electrical connector onto the instrument cluster, or as Nissan call it, the Combination Meter. This became apparent when the Fuel Contents Gauge and RH Turn warning light also started playing up. An Airbag Light on and a non-functioning Turn warning are both MOT failure items, so I need to fix it. See the following photos: -
Hopefully you can see my added labels as the where the offending pins are. I've disconnected, cleaned (although they didn't appear dirty) and reconnected each plug and also removed some of the tape from the wiring looms to try and ease any strain on the connectors. The RH Turn warning seems OK now but not the other two problems. If I reach my fingers over and press on the top of the grey connector where pins 12 and 20 are, all is well. But I can only do this with the trim removed and the cluster unbolted. By the time everything is reassembled, the problem comes back.
I don't fancy replacing the connector (if I can get one) as the loom doesn't come out very far from the dash. How can I make the existing connector seat down better for good continuity? The single locking clip is presently working, but that's only in the middle and perhaps age and heat has distorted the plastics?
What about: -
A. Using a rapid curing epoxy resin or superglue, sparingly on the connector shell. I'd need to hold it firmly down until set.
B. Using some kind of conductive grease on the pins. (Risk of causing short-circuits if it goes everywhere.)
C. Inserting a sliver of solder into each pin socket. (Don't want to bend the tiny pins and make things worse.)
D. Drill some holes (<1mm) and use 24 swg locking wire to firmly hold the connector halves together at each end. Obviously I'd need to route the wire clear of the contacts.
I must say I'm leaning towards 'D' but any other suggestions would be welcome.
Edited by JoeBolt on Sunday 16th July 19:29
I can imagine a few possible reasons:
The terminals are corroded or have relaxed so they no longer apply enough contact pressure. This seems the most likely possibility.
The terminals are damaged or incorrectly positioned in the housing. This can happen when a plug is forced into position when the terminals are misaligned. You can usually see this by inspecting the open end of the terminals.
The connector isn't fully home in its socket so the terminals aren't fully engaged. This sounds unlikely from your description but you could check it by looking at the relatively position of the terminals versus the plug.
None of these would be resolved by mechanically tying the plug into its housing.
If there is a problem with the terminals, you'd fix it by replacing the terminals within the existing plug, not by replacing the whole plug.
The terminals are corroded or have relaxed so they no longer apply enough contact pressure. This seems the most likely possibility.
The terminals are damaged or incorrectly positioned in the housing. This can happen when a plug is forced into position when the terminals are misaligned. You can usually see this by inspecting the open end of the terminals.
The connector isn't fully home in its socket so the terminals aren't fully engaged. This sounds unlikely from your description but you could check it by looking at the relatively position of the terminals versus the plug.
None of these would be resolved by mechanically tying the plug into its housing.
If there is a problem with the terminals, you'd fix it by replacing the terminals within the existing plug, not by replacing the whole plug.
I know the history of this car, so I'm pretty certain the instrument cluster has never been out before. Any misalignment damage to the terminals must have been done at the factory. Certainly possible given what I found when I was going over the rest of the SRS loom - cables stretched into place with very tight bends, etc.
It all works correctly when I press on the connector which is why I'm considering the locking wire method. I just need it to get through the next MOT in September.
In the meantime, I know where I can get another complete instrument cluster for free, or perhaps the cost of a pint. (So pretty expensive actually!) I might fit that one first and see what happens.
It all works correctly when I press on the connector which is why I'm considering the locking wire method. I just need it to get through the next MOT in September.
In the meantime, I know where I can get another complete instrument cluster for free, or perhaps the cost of a pint. (So pretty expensive actually!) I might fit that one first and see what happens.
Do you have a photo of the plug?
I am wondering if you might be able to remove the pins (well, sockets really as they will be the female companion to the pins on the cluster) and check to make sure they have a decent amount of sprung clamping force to them. They can often be removed by pressing in a visible barb and pushing/pulling them out.
If the pins were clean though I think my money would be on dry/cracked solder joints as some others have mentioned. Are you able to dismantle the cluster further to obtain access to the board? Might worth a cursory check on eBay to see if a spare - or indeed immediate replacement - can be picked up for not too much too.
I am wondering if you might be able to remove the pins (well, sockets really as they will be the female companion to the pins on the cluster) and check to make sure they have a decent amount of sprung clamping force to them. They can often be removed by pressing in a visible barb and pushing/pulling them out.
If the pins were clean though I think my money would be on dry/cracked solder joints as some others have mentioned. Are you able to dismantle the cluster further to obtain access to the board? Might worth a cursory check on eBay to see if a spare - or indeed immediate replacement - can be picked up for not too much too.
No photo of the plug, just a diagram above which I copied from the manual. But yes, the terminals should be removable with a bit of fiddling using a suitable implement.
However, I'm not intending to do anything else until I have the spare cluster. Fitting that to see what works and what doesn't is going to be my next step.
However, I'm not intending to do anything else until I have the spare cluster. Fitting that to see what works and what doesn't is going to be my next step.
Just to close this out, I fitted the replacement instrument cluster this morning and all appears well. (Touch wood.)
Not only that, the indicated mileage isn't very far off being correct, so I don't need to worry about that.
In time, I'll probably take apart the old cluster to see what I can find.
I'm glad I didn't need to remove the terminals from the connector, but here are a couple of photos for those interested. Airbag - Brown/White. Fuel Contents - Green.
[url]
|https://thumbsnap.com/9Rqeuhq2[/url]
Not only that, the indicated mileage isn't very far off being correct, so I don't need to worry about that.
In time, I'll probably take apart the old cluster to see what I can find.
I'm glad I didn't need to remove the terminals from the connector, but here are a couple of photos for those interested. Airbag - Brown/White. Fuel Contents - Green.
[url]|https://thumbsnap.com/9Rqeuhq2[/url]Gassing Station | Home Mechanics | Top of Page | What's New | My Stuff