Firewall wire routing P15C

[Vin's 49 Plymouth]

I'm at the point in my restoration of my P15C to install a new wire harness. The car had the front end torn apart (including most of the wires) when I bought it.

 

I need to know the original routing of the wires and cables through the fire wall. Diagrams don't tell which port they go through. Can you kind folks help a lad with this?

I've got new paint and new rubber on the firewall, so it's time.

 

Thank you.

Vince

 

Here is a photo of the harness after I sorted the circuits out.

 

 

[Eneto-55]

The wire harness passes through the oblong hole on the left side of the firewall (left side of engine, to your right as you face toward the back of the vehicle).  The other oblong hole (close to the center of the firewall) is where the temperature gauge tube goes.

 

[Vin's 49 Plymouth]

Eneto, Thank you for the response.

When I stripped the car there was one or two wires through the oval on the centerline. They were not terminated.

There are two other round holes? I think one is the hood release, which was not connected.

 

Thanks.

[Eneto-55]

The hood release cable exits through the side of the cowl - this is a pretty small round hole.  The larger round hole above the wire harness hole, that one I'm not sure of, either.  I also bought my car as a "basket case", and then I dismantled it a lot more, but that was back in 1980.  I had put the wiring harness back through after painting, but have it out now because the wiring has dried out completely in the years since then.  I'm wondering if that larger hole could be for the hand brake - just not sure.  Hopefully someone else will chime in as well.

 

Edit to add:  Or possibly the speedometer cable?  I have my dash & instrument cluster out of the car, too, so I cannot tell for sure where it would go through the firewall.

Edited September 6, 2020 by Eneto-55
adding later comment

[Andydodge]

Things that go thru various grommets and brackets on the firewall include speedo cable, handbrake cable, choke cable,  oil pressure line, water temperature sender line, various wires for lights, ignition etc........andyd 

[Eneto-55]

Just a quick note before heading off to church services.

 

I seem to recall that the rubber grommet for the oblong hole near the center of the firewall (behind the engine) has three holes.  Two of these I'm sure of, the temperature tube, and the oil pressure line.  My guess is that the third is the choke cable.  Then the heater cable would go through a different hole, unless that grommet has four holes.  

The round hole above the wiring harness access (oblong hole on left side of firewall) - I'm guessing now that that grommet must have two holes, one for the speedometer, and another for the handbrake cable.

 

But the best would be if someone could post a picture of the firewall on an assembled car, or just write out where everything goes.

[MarcDeSoto]

I found this pic on the Internet.  I think it is a 48 DeSoto.  It shows the hand brake coming out on the right side and the wiring harness coming out below from the football shaped opening.  It also shows the dash gauge cables coming out of the middle football shaped hole.  I'm not sure where the hood release cable comes out?

 

 

Edited September 7, 2020 by MarcDeSoto

[Eneto-55]

I found a discussion thread about rubber parts where I had posted a picture of the oblong grommet that is for the hole near the center of the firewall.  I said above that I thought it has 3 holes, but it has 5.

 

Here is that link:

In addition to the temperature tube, oil pressure line & possibly the heater cable, it would also have the windshield wiper motor vacuum line going through there.  Is there a return vacuum line, going back to the carb?  (I'll have to look at my wiper motor.)  Maybe the speedometer goes through there as well?  I'm realizing more & more how much I have forgotten in the 40 years since I took my car apart.  (If only there had been digital cameras back then....)

[Los_Control]

My thoughts, the football shaped hole is a clamp . It has screws you tighten to hold things tight. I would not think it is made for wiring or vacuum hose.

My truck I have the temp sending unit, oil pressure line, choke cable, throttle cable. (I am not sure the oil line belongs there)

Up above it is a small hole for the vacuum line, off to the right is a larger hole for the wiring to come through.

 

This is a truck and not your car so is different. The hole for the wiring comes out just to the side of the voltage regulator.

Is directly above the starter/main power wire

Is a short jog over to the foot dimmer switch ... then wanders up the inner fender to the lights.

 

I bet if you mount your voltage regulator, close by will be a larger hole for the main harness. And it will make sense how to map the wires.

The factory is not going to run 10 miles of wire, if they can do the job with 5 miles.

[greg g]

Vacuum hose for the wiper is one way, no return line is used. The hand throttle cable passes through the fire wall as well.

[Vin's 49 Plymouth]

Thank you all for your help. Every one of your posts have helped.

 

Being able to only work on the car once a week is tough. I am very anxious to get wires through so I can start the engine. I've never heard it run. 

With the full race cam and all the other things I did, it should sound really good. 

[Eneto-55]

Vin,

 

I've been looking for firewall photos (on this site), and the best ones I've seen so far are of a Dodge, but should be pretty similar.

 

Here is the discussion where I saw them:

https://p15-d24.com/topic/42736-need-a-photo-or-two/?tab=comments#comment-454885

[greg g]

Scan through the pics in the link, there is a pretty clear pic of the firewall protrusions about 10 pictures in.

 

https://m.facebook.com/nick.rich.96/posts/pcb.3886210374729194/?photo_id=10220165001774236&mds=%2Fphotos%2Fviewer%2F%3Fphotoset_token%3Dpcb.3886210374729194%26photo%3D10220165001774236%26profileid%3D100003888494382%26source%3D48%26ref%3Dm_notif%26notif_t%3Dcommerce_interesting_product%26_ft_%3Dtop_level_post_id.3886210374729194%3Acontent_owner_id_new.1202044858%3Acommerce_rank_obj.%7B%22viewer_id%22%3A100003888494382%2C%22target_id%22%3A3221019508016629%2C%22target_type%22%3A0%2C%22primary_position%22%3A-1%2C%22secondary_position%22%3A-1%2C%22search_query%22%3A%22%22%2C%22search_sid%22%3A%22%22%2C%22session_id%22%3A0%2C%22typeahead_sid%22%3A%22%22%2C%22ranking_signature%22%3A0%2C%22commerce_channel%22%3A507%2C%22commerce_type%22%3A2%2C%22ectr%22%3A0%2C%22value%22%3A0%2C%22original_value%22%3A0%2C%22model_scores%22%3A%7B%7D%2C%22upsell_candidate_ids%22%3A[]%2C%22upsell_type%22%3Anull%2C%22metadata%22%3A%7B%7D%2C%22ad_imp_delivery_data_binary%22%3Anull%2C%22ad_imp_delivery_data_array%22%3Anull%2C%22qp_renderer_type%22%3Anull%2C%22top_unit_ranking_score%22%3Anull%2C%22is_budget_upsell%22%3Afalse%2C%22is_pacer_applied%22%3Afalse%2C%22is_billboard_promotion_upsell%22%3Afalse%2C%22category_id%22%3Anull%2C%22candidate_score_map%22%3Anull%2C%22candidate_retrieval_source_map%22%3Anull%2C%22candidate_signature_map%22%3Anull%2C%22candidate_seller_id_map%22%3Anull%2C%22candidate_creation_time_map%22%3Anull%2C%22candidate_dense_features_map%22%3Anull%2C%22candidate_vertical_metadata_map%22%3Anull%2C%22candidate_buyer_product_rt_imp_v2_map%22%3Anull%2C%22vertical%22%3Anull%2C%22vertical_metadata%22%3Anull%2C%22dense_features%22%3Anull%2C%22collection_id%22%3Anull%2C%22theme_id%22%3Anull%2C%22buyer_product_rt_imp_v2%22%3A0%2C%22candidate_model_score_map%22%3Anull%2C%22client_time%22%3A0%2C%22last_rank_index%22%3A0%2C%22last_rank_time%22%3A0%2C%22creation_time%22%3A0%2C%22seller_id%22%3A0%2C%22other_user_id%22%3A-1%2C%22time_since_li%22%3A-1%2C%22response_time%22%3A-1%2C%22message_count%22%3A0%2C%22buyer_session_count%22%3A0%2C%22seller_session_count%22%3A0%2C%22hour_of_day%22%3A-1%2C%22ad_finder_request_id%22%3Anull%2C%22fpt_id%22%3Anull%2C%22retrieval_source_name%22%3Anull%7D%3Apage_id.1772194882797431%3Aphoto_id.10220165001014217%3Astory_location.26%3Astory_attachment_style.group_sell_product_item%3Atds_flgs.3%3Apage_insights.%7B%221772194882797431%22%3A%7B%22page_id%22%3A1772194882797431%2C%22page_id_type%22%3A%22group%22%2C%22actor_id%22%3A1202044858%2C%22dm%22%3A%7B%22isShare%22%3A0%2C%22originalPostOwnerID%22%3A0%7D%2C%22psn%22%3A%22EntGroupMallPostCreationStory%22%2C%22post_context%22%3A%7B%22object_fbtype%22%3A657%2C%22publish_time%22%3A1599497722%2C%22story_name%22%3A%22EntGroupMallPostCreationStory%22%2C%22story_fbid%22%3A[3886210374729194]%7D%2C%22role%22%3A1%2C%22sl%22%3A26%7D%7D%26__tn__%3DEH%26cached_data%3Dfalse%26ftid%3D&mdp=1&mdf=1

[Eneto-55]

3 hours ago, greg g said:

Scan through the pics in the link, there is a pretty clear pic of the firewall protrusions about 10 pictures in.

 

 

 

Greg,

WOW!  I don't think I've ever seen a P15 so rotted out!  (I had seen the pictures of the trim before, but not the car itself.)  

(Not sure what was wrong, but I could only see the first picture at first.  I think that if your link doesn't work for others, they can try this: https://m.facebook.com/nick.rich.96/posts/pcb.3886210374729194

 

I see some parts I could probably use, but the car is on Long Island.  Long ways from me, or any place I would want to go.

 

Vin,

 

I found some more photos from cars for sale ads I've seen over the years (going back a bit over 10 years ago...)

In the course of doing this search, I have discovered more parts that I am missing, like I don't have the cad plated fastener for the round hole on the right side of the cowl, nor the second oblong one.  And I'm pretty sure I had replated all of those parts.  Oh well.

 

 

 

Edited September 8, 2020 by Eneto-55

[Vin's 49 Plymouth]

Thanks Greg and Eneto,

I'm visiting the president of the Walter P Chrysler club (for the northwest region) next door in Woodinville today, so I will get some info from him as well. I got a lot of great information from all of you.

Thanks so much. 

I will tag this one solved.